Unit 3 Ships in the Desert
Ships in the Desert
Ships in the Desert
AL Gore
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I was standing in the sun on the hot steel deck of a fishing ship capable of processing a fifty-ton catch on a good day. But it wasn' t a good day. We were anchored in what used to be the most productive fishing site in all of central Asia, but as I looked out over the bow , the prospects of a good catch looked bleak. Where there should have been gentle blue-green waves lapping against the side of the ship, there was nothing but hot dry sand – as far as I could see in all directions. The other ships of the fleet were also at rest in the sand, scattered in the dunes that stretched all the way to the horizon . Ten year s ago the Aral was the fourth-largest inland sea in the world, comparable to the largest of North America's Great Lakes. Now it is disappearing because the water that used to feed it has been diverted in an
ill-considered irrigation scheme to grow cotton In the user t. The new shoreline was almost forty kilometers across the sand from where the fishing fleet was now permanently docked. Meanwhile, in the nearby town of Muynak the people were still canning fish – brought not from the Aral Sea but shipped by rail through Siberia from the Pacific Ocean, more than a thousand miles away.
My search for the underlying causes of the environmental crisis has led me to travel around the world to examine and study many of these images of destruction. At the very bottom of the earth, high in the Trans-Antarctic Mountains, with the sun glaring at midnight through a hole in the sky, I stood in the unbelievable coldness and talked with a scientist in the late tall of 1988 about the tunnel he was digging through time. Slipping his parka back to reveal a badly burned face that was cracked and peeling, he pointed to the annual layers of ice in a core sample dug from the glacier on which we were standing. He moved his finger back in time to the ice of two decades ago. "Here's where the U. S Congress passed the Clean Air Act, ‖ he said. At the bottom of the world, two continents away from Washington, D. C., even a small reduction in one country's emissions had changed the amount of pollution found in the remotest end least accessible place on earth.
But the most significant change thus far in the earth' s atmosphere is the one that began with the industrial r evolution early in the last century and has picked up speed ever since. Industry meant coal, and later oil, and we began to burn lots of it – bringing rising levels of carbon dioxide (CO2) , with its ability to trap more heat in the atmosphere and slowly warm the earth. Fewer than a hundred yards from the South Pole, upwind from the ice runway where the ski plane lands and keeps its engines running to prevent the metal parts from freeze-locking together, scientists monitor the air sever al times ever y day to chart the course of that inexorable change. During my visit, I watched one scientist draw the results of that day's
measurements, pushing the end of a steep line still higher on the graph. He told me how easy it is – there at the end of the earth – to see that this enormous change in the global atmosphere is still picking up speed.
Two and a half years later I slept under the midnight sun at the other end of our planet, in a small tent pitched on a twelve-toot-thick slab of ice floating in the frigid Arctic Ocean. After a hearty breakfast, my companions and I traveled by snowmobiles a few miles farther north to a rendezvous point where the ice was thinner – only three and a half feet thick – and a nuclear submarine hovered in the water below. After it crashed through the ice, took on its new passengers, and resubmerged, I talked with scientists who were trying to measure more accurately the thickness of the polar ice cap, which many believe is thinning as a re-suit of global warming. I had just negotiated an agreement between ice scientists and the U. S. Navy to secure the re-lease of previously top secret data from submarine sonar tracks, data that could help them learn what is happening to the north polar cap. Now, I wanted to see the pole it-self, and some eight hours after we met the submarine, we were crashing through that ice, surfacing, and then I was standing in an eerily beautiful snowcape, windswept and sparkling white, with the horizon defined by little hummocks, or "pressure ridges " of ice that are pushed up like tiny mountain ranges when separate sheets collide. But here too, CD, levels are rising just as rapidly, and ultimately temperature will rise with them – indeed, global warming is expected to push temperatures up much more rapidly in the polar regions than in the rest of the world. As the polar air warms, the ice her e will thin; and since the polar cap plays such a crucial role in the world's weather system, the consequences of a thinning cap could be disastrous.
Considering such scenarios is not a purely speculative exercise. Six months after I returned from the North Pole, a team of scientists reported dramatic changes in the pattern of ice distribution in the Arctic, and a second team reported a still controversialclaim (which a variety of data now suggest) that, over all, the north polar cap has thinned by 2 per cent in just the last decade. Moreover, scientists established several years ago that in many land areas north of the Arctic Circle, the spring snowmelt now comes earlier every year, and deep in the tundra below, the temperature e of the earth is steadily rising.
As it happens, some of the most disturbing images of environmental destruction can be found exactly halfway between the North and South poles – precisely at the equator in Brazil – where billowing clouds of smoke regularly black-en the sky above the immense but now threatened Amazon rain forest. Acre by acre, the rain forest is being burned to create fast pasture for fast-food beef; as I learned when I went there in early 1989, the fires are set earlier and earlier in the dry season now, with more than one Tennessee's worth of rain forest being slashed and burned each year. According to our guide, the biologist Tom Lovejoy, there are more different species of birds in each square mile of the Amazon than exist in all of North America – which means we are silencing thousands of songs we have never even heard.
But one doesn't have to travel around the world to wit-ness humankind's assault on the earth. Images that signal the distress of our global environment are
now commonly seen almost anywhere. On some nights, in high northern latitudes, the sky itself offers another ghostly image that signals the loss of ecological balance now in progress. If the sky is clear after sunset -- and it you are watching from a place where pollution hasn't blotted out the night sky altogether -- you can sometimes see a strange kind of cloud high in the sky. This "noctilucent cloud" occasionally appears when the earth is first cloaked in the evening dark-ness; shimmering above us with a translucent whiteness, these clouds seem quite unnatural. And they should: noctilucent clouds have begun to appear more often because of a huge buildup of methane gas in the atmosphere. (Also called natural gas, methane is released from landfills , from coal mines and rice paddies, from billions of termites that swarm through the freshly cut forestland, from the burning of biomass and from a variety of other human activities. ) Even though noctilucent clouds were sometimes seen in the past., all this extra methane carries more water vapor into the upper atmosphere, where it condenses at much higher altitudes to form more clouds that the sun's rays still strike long after sunset has brought the beginning of night to the surface far beneath them.
What should we feel toward these ghosts in the sky? Simple wonder or the mix of emotions we feel at the zoo? Perhaps we should feel awe for our own power: just as men "ear tusks from elephants’ heads in such quantity as to threaten the beast with extinction, we are ripping matter from its place in the earth in such volume as to upset the balance between daylight and darkness. In the process, we are once again adding to the threat of global warming, be-cause methane has been one of the fastest-growing green-house gases, and is third only to carbon dioxide and water vapor in total volume, changing the chemistry of the upper atmosphere. But, without even considering that threat, shouldn't it startle us that we have now put these clouds in the evening sky which glisten with a spectral light? Or have our eyes adjusted so completely to the bright lights of civilization that we can't see these clouds for what they are – a physical manifestation of the violent collision between human civilization and the earth?
Even though it is sometimes hard to see their meaning, we have by now all witnessed surprising experiences that signal the damage from our assault on the environment --whether it's the new frequency of days when the temperature exceeds 100 degrees, the new speed with which the -un burns our skin, or the new constancy of public debate over what to do with growing mountains of waste. But our response to these signals is puzzling. Why haven't we launched a massive effort to save our environment? To come at the question another way' Why do some images startle us into immediate action and focus our attention or ways to respond effectively? And why do other images, though sometimes equally dramatic, produce instead a Kin. of paralysis, focusing our attention not on ways to respond but rather on some convenient, less painful distraction?
Still, there are so many distressing images of environ-mental destruction that sometimes it seems impossible to know how to absorb or comprehend them. Before considering the threats themselves, it may be helpful to classify them and thus begin to organize our thoughts and feelings so that we may be able to respond
appropriately.
A useful system comes from the military, which frequently places a conflict in one of three different categories, according to the theater in which it takes place. There are "local" skirmishes, "regional" battles, and "strategic" conflicts. This third category is reserved for struggles that can threaten a nation's survival and must be under stood in a global context. Environmental threats can be considered in the same way. For example, most instances of water pollution, air pollution, and illegal waste dumping are essentially local in nature. Problems like acid rain, the contamination of
under-ground aquifers, and large oil spills are fundamentally regional. In both of these categories, there may be so many similar instances of particular local and regional problems occurring simultaneously all over the world that the patter n appears to be global, but the problems themselves are still not truly strategic because the operation of- the global environment is not affected and the survival of civilization is not at stake.
However, a new class of environmental problems does affect the global ecological system, and these threats are fundamentally strategic. The 600 percent increase in the amount of chlorine in the atmosphere during the last forty years has taken place not just in those countries producing the chlorofluorocarbons responsible but in the air above every country, above Antarctica, above the North Pole and the Pacific Ocean – all the way from the surface of the earth to the top of the sky. The increased levels of chlorine disrupt the global process by which the earth regulates the amount of ultraviolet radiation from the sun that is allowed through the atmosphere to the surface; and it we let chlorine levels continue to increase, the radiation levels will al-so increase – to the point that all animal and plant life will face a new threat to their survival.
Global warming is also a strategic threat. The concentration of carbon dioxide and other heat-absorbing molecules has increased by almost 25 per cent since World War II, posing a worldwide threat to the earth's ability to regulate the amount of heat from the sun retained in the atmosphere. This increase in heat seriously threatens the global climate equilibrium that determines the pattern of winds, rainfall, surface temperatures, ocean currents, and sea level. These in turn determine the distribution of vegetative and animal life on land and sea and have a great effect on the location and pattern of human societies.
In other words, the entire relationship between humankind and the earth has been transformed because our civilization is suddenly capable of affecting the entire global environment, not just a particular area. All of us know that human civilization has usually had a large impact on the environment; to mention just one example, there is evidence that even in prehistoric times, vast areas were sometimes intentionally burned by people in their search for food. And in our own time we have reshaped a large part of the earth's surface with concrete in our cities and carefully tended rice paddies, pastures, wheat fields, and other croplands in the countryside. But these changes, while sometimes appearing to be pervasive , have, until recently, been relatively trivial factors in the global ecological sys-tem. Indeed, until our lifetime, it was always safe to assume that nothing we did or could do would have
any lasting effect on the global environment. But it is precisely that assumption which must now be discarded so that we can think strategically about our new relationship to the environment.
Human civilization is now the dominant cause of change in the global environment. Yet we resist this truth and find it hard to imagine that our effect on the earth must now be measured by the same yardstick used to calculate the strength of the moon's pull on the oceans or the force of the wind against the mountains. And it we are now capable of changing something so basic as the relationship between the earth and the sun, surely we must acknowledge a new responsibility to use that power wisely and with appropriate restraint. So far, however, We seem oblivious of the fragility of the earth's natural systems.
This century has witnessed dramatic changes in two key factors that define the physical reality of our relation-ship to the earth: a sudden and startling surge in human population, with the addition of one China's worth of people every ten years, and a sudden acceleration of the scientific and technological revolution, which has allowed an almost unimaginable magnification of our power to affect the world around us by burning, cutting, digging, moving, and trans-forming the physical matter that makes up the earth. The surge in population is both a cause of the changed relationship and one of the clearest illustrations of how startling the change has been, especially when viewed in a historical context. From the emergence of modern humans 200 000 years ago until Julius Caesar's time, fewer than 250 million people walked on the face of the earth. When Christopher Columbus set sail for the New World 1500 years later, there were approximately 500 million people on earth. By the time Thomas Jefferson wrote the Declaration of Independence in 1776, the number had doubled again, to 1 billion. By midway through this century, at the end of World War II, the number had risen to just above 2 billion people. In other words, from the beginning of humanity's appearance on earth to 1945, it took more than ten thousand generations to reach a world population of 2 billion people. Now, in the course of one human lifetime -- mine -- the world population will increase from 2 to more than 9 million, and it is already more than halfway there.
Like the population explosion, the scientific and technological revolution began to pick up speed slowly during the eighteenth century. And this ongoing revolution has also suddenly accelerated exponentially. For example, it is now an axiom in many fields of science that more new and important discoveries have taken place in the last ten years that. in the entire previous history of science. While no single discover y has had the kind of effect on our relationship to the earth that unclear weapons have had on our relationship to warfare, it is nevertheless true that taken together, they have completely transformed our cumulative ability to exploit the earth for sustenance -- making the consequences, of unrestrained exploitation every bit as unthinkable as the consequences of unrestrained nuclear war.
Now that our relationship to the earth has changed so utterly, we have to see that change and understand its implications. Our challenge is to recognize that the startling images of environmental destruction now occurring all over the world have much more in common than their ability to shock and awaken us. They are
symptoms of an underlying problem broader in scope and more serious than any we have ever faced. Global warming, ozone depletion, the loss of living species, deforestation -- they all have a common cause: the new relationship between human civilization and the earth's natural balance. There are actually two aspects to this challenge. The first is to realize that our power to harm the earth can in-deed have global and even permanent effects. The second is to realize that the only way to understand our new role as a co-architect of nature is to see ourselves as part of a complex system that does not operate according to the same simple rules of cause and effect we are used to. The problem is not our effect on the environment so much as our relationship with the environment. As a result, any solution to the problem will require a careful assessment of that relationship as well as the complex interrelationship among factors within civilization and between them and the major natural components of the earth's ecological system.
There is only one precedent for this kind of challenge to our thinking, and again it is military. The invention of nuclear weapons and the subsequent development by the Unit-ed States and the Soviet Union of many thousands of strategic nuclear weapons forced a slow and painful recognition that the new power thus acquired forever changed not only the relationship between the two superpowers but also the relationship of humankind to the institution at war-fare itself. The consequences of all-out war between nations armed with nuclear weapons suddenly included the possibility of the destruction of both nations – completely and simultaneously. That sobering realization led to a careful reassessment of every aspect of our mutual relationship to the prospect of such a war. As early as 1946 one strategist concluded that strategic bombing with missiles "may well tear away the veil of illusion that has so long obscured the reality of the change in warfare – from a fight to a process of destruction.‖
Nevertheless, during the earlier stages of the nuclear arms race, each of the superpower s assumed that its actions would have a simple and direct effect on the thinking of the other. For decades, each new advance in weaponry was deployed by one side for the purpose of inspiring fear in the other. But each such deployment led to an effort by the other to leapfrog the first one with a more advanced deployment of its own. Slowly, it has become apparent that the problem of the nuclear arms r ace is not primarily caused by technology. It is complicated by technology, true; but it arises out of the relationship between the superpowers and is based on an obsolete understanding of what war is all about.
The eventual solution to the arms race will be found, not in a new deployment by one side or the other of some ultimate weapon or in a decision by either side to disarm unilaterally , but ratter in new understandings and in a mutual transformation of the relationship itself. This transformation will involve changes in the technology of weaponry and the denial of nuclear technology to rogue states. But the key changes will be in the way we think about the institution of war far e and about the relationship between states.
The strategic nature of the threat now posed by human civilization to the global environment and the strategic nature of the threat to human civilization now posed
by changes in the global environment present us with a similar set of challenges and false hopes. Some argue that a new ultimate technology, whether nuclear power or genetic engineering, will solve the problem. Others hold that only a drastic reduction of our reliance on technology can improve the conditions of life -- a simplistic notion at best. But the real solution will be found in reinventing and finally healing the relationship between civilization and the earth. This can only be accomplished by undertaking a careful reassessment of all the factors that led to the relatively recent dramatic change in the relationship. The transformation of the way we relate to the earth will of course involve new technologies, but the key changes will involve new ways of thinking about the relationship itself.
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NOTES
I) Al Gore: born in 1948 in Washington D. C., U. S. Senator (1984-1992) from the State of Tennessee,and U. S. Vice-President ( l 992-) under President Bill Clinton. He is the author of the book Earth in the Balance from which this piece is taken. 2) Aral Sea: inland sea and the world’s fourth largest lake, c. 26 000 sqmiles, SW Kazakhstan and NW Uzbekhstan, E of the Caspian Sea
3) Great Lakes: group of five freshwater lakes, Central North America, between the United States and Canada, largest body of fresh water in the world. From west to east, they are Lake Superior,Lake Michigan,Lake Huron, Lake Erie, and Lake Ontario.
4) Trans-Antarctic Mountains: mountain chain stretching across Antarctica from Victoria I and to Coats I and; separating the E Antarctic and W Antarctic subcontinents
5) Clean Air Act: one of the oldest environmental laws of the U. S., as well as the most far-reaching, the costliest, and the most controversial. It was passed in 1970.
6) Washington D. C.: capital of the United States. D. C. (District of Columbia).is added to distinguish it from the State of Washington and 3 other cities in the U. S bearing the sonic name.
7) freeze-locking: the metal parts are frozen solid and unable to move freely
8)midnight sun: phenomenon in which the sun remains visible in the sky for 24 hours or longer, occurring only in the polar regions
9)global warming; The earth is getting warmer. The temperature of the earth's atmosphere and its surface is steadily rising.
10) Submarine sonar tracks: the term sonar is an acronym for sound navigation ranging. It is used for communication between submerged submarines or between a submarine and a surface vessel, for locating mines and underwater hazards to navigation, and also as a fathometer, or depth finder.
11) greenhouse (effect): process whereby heat is trapped at the surface of the earth by the atmosphere. An increase of man-made pollutants in the atmosphere will lead to a long-term warming of the earth's climate.
12) Julius Caesar: (102? B. C -- 44 B. C:. ), Roman statesman and general
13) Christopher Columbus: ( 1451-1506), discoverer of America, born Genoa, Italy
14) Thomas Jefferson: (17-13-1826 ), 3d President of the United
States(1801-1809), author of the Declaration of Independence.
15) Declaration of Independence: full and formal declaration adopted July 4,1776, by representatives of the thirteen colonies in North America announcing the separation of those colonies from Great Britain and making them into the United States
16)Ozone depletion: A layer of ozone in the stratosphere prevents most ultraviolet and other high-energy radiation, which is harmful to life, from penetrating to the earth's surface.Some.environmental, scientists fear that certain man-made pollutants, e.g. nitric oxide, CFCs(Chlorofluorocarbons), etc., may interfere with the delicate balance of reactions that maintains the ozone’ s concentration, possibly leading to a drastic depletion of stratospheric ozone. This is now happening in the stratosphere above the polar
Ships in the Desert 课文讲解/Detailed Study
Ships in the Desert
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Detailed Study
1. Ships in the Desert [image-7]: Ships anchored in the desert. This is an
eye-catching title and it gives an image that people hardly see. When readers read the title, they can’t help wondering why and how.
Paragraph 1. typical example of environmental destruction
[image-7]
2. capable of processing a fifty-ton catch on a good day: having the ability of cleaning and preparing for marketing or canning fifty-tons of fish on a productive day.
catch: the amount of something caught; in the sentence it refers to the amount of fish caught e.g. The boat brought back a big catch of fish.
3. but as I looked out over the bow, the prospects of a good catch looked bleak:
a good catch did not look promising / hopeful.
This is obviously an understatement because with sand all around there was no chance of catching fish, to say nothing of catching a lot of fish.
bow[audio-1] : the front part of a ship
ant. stern
compare: bow[audio-2]: v. & n. to bend the upper part of the body forward, as a
way of showing respect, admitting defeat, etc.
bow [audio-3]: n. a weapon for shooting arrow
a long thin piece of wood with a tight string fastened along it, used for playing musical instruments that have strings
a knot formed by doubling a string or cord into two curved pieces, and used for decoration in the hair, in tying shoes, etc
bleak: a) If a situation is bleak, it is bad, and seems unlikely to improve.
e.g. His future looked bleak.
bleak prospect; the bleakness of the post war years
b) If a place is bleak, it looks cold, bare, and unattractive
e.g. the bleak coastline
c) When the weather is bleak, it is cold, dull, and unpleasant
e.g. the bleak winters
d) If someone looks or sounds bleak, they seem depressed, hopeless, or unfriendly
e.g. his bleak features
bleakly adv.
e.g. He stared bleakly ahead.
―What,‖ he asked bleakly, ―are these?‖
4. waves lapping against the side of the ship: waves touching the side of the ship gently and makes a soft sound lap can also be used as a noun.
e.g. Your lap is the flat area formed by your thighs when you are sitting down. Her youngest child was asleep in her lap.
He placed the baby on the woman’s lap.
In a race, when you say that a competitor has completed a lap when he or she has gone round the course race.
5. as far as I could see in all direction: that extended as far as the eye could see;
6. that stretched all the way to the horizon: that extended to the far off place where the sky meet the earth
7. comparable: something that is comparable to something else is a) as good as/ as big as/ as important as the other thing; b) similar to the other thing
e.g. This dinner is comparable to the best French cooking.
Our house is not comparable with yours. Ours is just a small hut while yours is a palace.
8. Now it is disappearing because the water that used to feed it has been diverted in an ill-considered irrigation scheme to grow cotton in the dessert: Now it is becoming smaller and smaller because the water that used to flow into the sea has been turned away to irrigate the land created in the desert to grow cotton. The
scheme was an ill-conceived one because it failed to take into consideration the ecological effect.
9. dock: v. anchor, moor
Paragraph 2. thesis statement: travel around the world to check and study cases in order to find out the basic causes behind the environmental crisis [image-8]
10. My search for the underlying causes of the environmental crisis has led me to travel around the world to examine and study many of these images of destruction: I travelled around the world because I wanted to see, check and study cases of such destruction in order to find out the basic causes behind the environmental crisis.
This sentence is the thesis statement, expressing the main idea and indicating the development of a causal essay.
images of destruction: typical examples of destruction
11. the sun glaring at midnight through a hole in the sky: the sun shining at midnight through the ozone depletion
[image-9]
midnight sun: phenomenon occurring only in the polar regions
a hole: ozone depletion 臭氧层空洞
12. about the tunnel he was digging through time: about the tunnel he was drilling for samples from the glacier, which estimates the time. The deeper he drilled, the farther the sample in time; in other words, the surface of the glacier [image-10] is an indication of recent time while the deeper part of the glacier tells of situation of a much more remote period.
13. Slipping his parka back to reveal a badly burned face that was cracked and peeling [image-11]: Pushing his parka back, he revealed a badly burned face because of overexposure to direct sunlight; on the face there were lines that were split open and pieces of skin were coming down.
parka: [image-12] n. waterproof jacket with a hood attached (as worn for skiing, mountain climbing, etc.)
14. He moved his finger back in time to the ice of two decades ago: Following the layers of ice in the core sample, his finger came to the place where the layer of ice was formed 20 years ago.
15. two continents: South America and Antarctica
16. emission: the amount of pollutants discharged
17. least accessible place on earth: the place which is the most difficult to get to in the world
Paragraph 3. the global warming seen in the Antarctic [image-13]
18. Industry meant coal: the development of industry meant the use of large amount of coal as fuel to generate power.
19. bringing rising levels of carbon dioxide: making the amount of carbon dioxide in the atmosphere grow
20. with its ability to trap more heat in the atmosphere and slowly warm the earth: heat cannot easily get through carbon dioxide and go into the high altitude so carbon dioxide plays the role of a cover, keeping the heat near the earth.
21. the part after the dash (--) serves as an adverbial of result
22. upwind from the ice runaway where the ski plane lands and keeps its engines running to prevent the metal parts from freeze-locking together, scientists monitor the air several times every day to chart the course of that inexorable change: upwind from the ice runaway where the ski plane lands and keeps its engines running so that the metal parts will not be frozen solid, scientists watch the air several times every day to mark the course of that unalternable change.
upwind: in the direction from which the wind is blowing or usually blows
ice runway : runway is a strip of paved ground for use by airplanes in taking off and landing, and here in the South Pole the runway is a strip of ice ground
to prevent the metal parts from freeze-locking together: to stop the metal parts from being frozen solid
monitor the air: watch or check on the air
to chart the course: to show the onward movement on an outline map inexorable: that cannot be changed; unalternable
e.g. the inexorable rise in the cost of living
23. graph: usually a mathematical diagram
Paragraph 4. a thinning cap as the result of Arctic air warms [image-14]
24. pitch: pitch a tent means put up a tent
e.g. They pitched their tent near the stream.
They pitched their tent at the edge of the field.
25. slab: A slab of something is a thick flat piece of it.
e.g. a slab of rock; a concrete slab; a slab of cheese
26. frigid: cold; icy; freezing
e.g. frigid weather
27. a hearty breakfast: a satisfying and rich breakfast
to describe meals: sumptuous dinner; humble bread and cheese; square meal
28. snowmobile [image-15]: a kind of motor vehicle for traveling over snow, usually with steer able runners at the front and tractor treads at the rear
29. rendezvous point: the place where a submarine was to pick them up rendezvous: a) A rendezvous is a meeting often a secret one, that you have arranged with someone for a particular time and place.
e.g. We make a dawn rendezvous.
b) A rendezvous is a place where you have arranged to meet somebody often secretly.
e.g. I met him at a secret rendezvous outside the city.
30. hover: to wait close by, especially in an overprotective, insistent or anxious way
When a bird or insect hovers, it stays in the same position in the air by moving its wings very quickly.
If somebody is hovering, they are waiting in one place, for example, because they cannot decide what to do.
e.g. A figure hovered uncertainly in the doorway.
31. After it crashed through the ice, took on its new passengers, and resubmerged: After it broke through the ice, picked up it new passengers, and went below the surface of water again
emerge: appear
submerge: go below the surface of water
32. the polar ice cap [image-14]: 极地冰冠
33. to secure the release of previously top secret data: to ensure the making public of data which was originally classified as top secret .
34. from submarine sonar tracks: obtained from submarine sonar tracks sonar: [U] (an acronym for sound navigation ranging) an apparatus using sound waves for finding the position of underwater objects, such as mines or submarines 声纳（利用声波探测如水雷或潜艇等的水底目标的仪器）
Baiqi dolphins [image-16]:have sonar. Bats have sonar.
35. and then I was standing in an eerily beautiful snowscape, windswept and sparkling white, with the horizon defined by little hummocks, or ―pressure ridges‖ of
ice that are pushed up like tiny mountain ranges when separate sheets collide: and then I was standing in the vast scene of snow which was fearfully beautiful, windswept and shining white, with the stretch of ice field characterized by small ridges because of the force of the collision of the separate layers.
eerily: mysteriously or uncannily, especially in such a way as to frighten or disturb snowscape: scene of snow. Compare with landscape and seascape.
windswept: swept by or exposed to winds
with the horizon defined by little hummocks: with stretch of ice field characterized by small ridges
36. the ice here will thin: the ice here will become thin
37. the consequences of a thinning cap could be disastrous: the result of a thinning cap may indicate the possibilities of disasters
could: the word indicates ―possibilities‖
Paragraph 5. the rising temperature of the earth[image-17]
38. Considering such scenarios is not a purely speculative exercise: Thinking about how a series of events might happen as a consequence of the thinning of the Polar cap is not just a kind of practice in conjecture / speculation, it has got practical value.
scenario: a) an outline for an proposed or planned series of events, real or imagined 方案
b) the scenario of a film is a piece of writing that gives an outline of the story 脚本speculative: meditating; thinking; pondering; guessing
39. the pattern of ice distribution: the regular way ice is distributed
40. a still controversial claim: a statement which some scientists still do not completely accept
41. which a variety of data now suggest: data coming from different sources point to this conclusion
42. the Arctic Circle [image-18]: an imaginary line drawn round the world at a certain distance from the most northern point (the North Pole), north of which there is no darkness for six months of each year and almost no light for the other six months. cf. the Antarctic Circle
43. tundra [image-19]: any of the vast, nearly level, treeless plains of the Arctic regions
Paragraph 6. the disturbing images of environmental destruction at the
equator[image-20]
44. billowing: large swelling mass of
billow v. When smoke or cloud billows, it moves slowly upwards or across the sky
45. Amazon rain forest[image-21]: The Brazilian Amazon contains about a third of the Earth's remaining tropical forest and a very high portion of its biological diversity. One hectare (2.47 acres) of Amazonian moist forest contains more plant species than all of Europe. Yet still it is being destroyed just like other rainforests around the world.
46. Acre by acre, the rain forest is being burned to create fast pasture for
fast-food beef: Bit by bit trees in the rain forest are felled and the land is cleared and turned into pasture where cattle can be raised quickly and slaughtered and the beef can be used in hamburgers.
Pay attention to the connection of the two ―fasts‖ in fast pasture and fast food. With that comes the ―fast‖ disappearance of the rain forest.
fast pasture for fast-food beef: alliteration
47. the dry season: ant. in the wet season—the rainy season
similarly: the football season, the breeding season, the planting season, the holiday season, the harvest season, the cold season, the tourist season, the game season, a season of film
in season: If a fruit or vegetable is in season, it is the time of year when it is time for eating and it’s widely available.
Ant. be out of season
season v. e.g. season the food with salt
48. with more than one Tennessee’s worth of rain forest being slashed and burned each year: the area of rain forest burned in one year is bigger than the state of Tennessee.
worth: equal in area or size
slash: cut with a sweeping stroke
If you slash something, you make a long, deep cut in it.
e.g. Jack’s face had been slashed with broken glass.
49. which means we are silencing thousands of songs we have never even heard: Since miles of forest are being destroyed and the habitat for these rare birds no longer exists, thousands of birds which we have not even had a chance to see will become extinct.
Paragraph 7. images of destruction seen almost anywhere [image-22
https://www.doczj.com/doc/bf16741383.html,/noctilucent_clouds/pix.html ]
50. Images that signal the distress of our global environment are now commonly seen almost anywhere: Typical examples showing the dangerous environmental situation in the world can be found almost anywhere.
51. On some nights, in high northern latitudes, the sky itself offers another ghostly image that signals the loss of ecological balance now in progress: On some nights, in the area at a high northern latitude, the sky alone presents another example of ill omen showing there is ecological imbalance and this kind of imbalance is developing.
latitude (s): an area at a particular latitude
in high northern latitude 在北纬高纬度地区
cf. longitude经度
52. blot out: hide entirely; obscure
If one thing blots out another thing, it is in front of the other thing and prevents it from being seen.
e.g. The dust cloud blotted out the sun.
53. This ―noctilucent cloud‖[image-22] occasionally appears when the earth is first cloaked in the evening darkness; shimmering above us with a translucent whiteness, these clouds seem quite unnatural: This ―luminous cloud‖ occasionally appears when the earth is first hidden in the evening darkness; shining unsteadily above us with a partially transparent whiteness, these clouds don’t seem natural. noctilucent cloud: nocti- means night; lucent means shining, translucent designating or of a luminous cloud visible at night
to cloak: to conceal; hide
shimmer: shine with an unsteady light
translucent: partially transparent
54. because of a huge buildup of methane gas in the atmosphere: because there has been a big increase of methane gas in the atmosphere
55. methane is released from landfills, from coal mines and rice paddies, from billons of termites that swarm through the freshly cut forestland, from the burning of biomass and from a variety of other human activities: methane is emitted from garbage disposal, from coal mines and rice fields, from billions of termites （白蚁）[image-23]moving in large numbers through the freshly cut forestland, from the burning of amount of living organism in a particular area and from a variety of other human activities.
release: let go; emit
swarm: to move in large numbers
e.g. As the fire spread, people came swarming out of the building.
The photographers swarmed round her.
56. Even though noctilucent clouds were sometimes seen in the past, all this extra methane carries more water vapor into the upper atmosphere, where it condenses at much higher altitudes to form more clouds that the sun’s rays still strike long after sunset has brought the beginning of night to the surface far beneath them: The implication is that the night comes earlier than the upper part. The balance between day and night is broken. altitudes: a high area e.g. At high altitudes it is difficult to breathe.
Paragraph 8. human attitudes towards the images of destruction [imgage-24 ]
57. What should we feel toward these ghosts in the sky: What should our attitude be toward these noctilucent clouds in the sky?
58. Simple wonder or the mix of emotions we feel at the zoo: Should it only be
a feeling of surprise and admiration or a combination of different feelings we experience in the zoo?
the mix of emotions we feel at the zoo: on the one hand we feel excited about seeing those animals, but on the other hand, we feel sorry for them because they have been deprived of freedom.
59. Perhaps we should feel awe for our own power: Perhaps we should feel amazed and frightened at our own power.
60. just as men tear tusks from elephants’ heads in such quantity as to threaten the beast with extinction: men are killing such large number of elephants for their tusks that the species will soon extinguish.
61. we are ripping matter from its place in the earth in such volume as to upset the balance between daylight and darkens: we are using and destroying resources in such a big amount that we are disturbing the balance between daylight and darkness.
rip: tear; When you rip something or when it rips, it is torn violently.
e.g. The poster had been ripped to pieces.
Two of the canvas bags had been ripped
in such volume: in such quantity
upset: When the word is used as a verb or a predicative, the second syllable is stressed; When it is used as an adjective in an attributive position, the first syllable is stressed.
e.g.: You are up`set. I’ve got an `upset stomach.
to upset the balance: to cause something to go wrong
62. greenhouse gases, and is third only to carbon dioxide and water vapor in total volume: gases that will trap heat at the surface of the earth like a greenhouse and ranks third only to carbon dioxide and water vapor in total volume. This means
of all the gases, water vapor occupies the largest portion, carbon dioxide the second. Methane-natural gas, greenhouse gases- the third
greenhouse: A greenhouse is a glass building in which you grow plants that need to be protected from cold weat her, wind or frost. Here it’s a metaphor.
third only to : similarly second only to
e.g. He is second only to his elder brother.
63. changing the chemistry of the upper atmosphere: changing the chemical composition of the upper atmosphere
64. But, without even considering that threat, shouldn’t it startle us that we have now put these clouds in the evening sky which glisten with a spectral light? Or have our eyes adjusted so completely to the bright lights of civilization that we can’t see these clouds for what they are—a physical manifestation of the violent collision between human civilization and the earth? These are two rhetorical questions.
As for rhetorical questions, there’s no need to give the answer, and the answer is implied in the questions. If the rhetorical question is negative, the answer is positive and vice versa. So the first rhetorical question means it should s tartle us…; the second one means our eyes haven’t adjusted so completely to the bright lights of civilization that we can’t see….
startle: to alarm suddenly or unexpectedly
glisten: to shine or sparkle with reflected light, as a wet or polished surface spectral: like a ghost; ghostly
Or have our eyes adjusted so completely to the bright lights of civilization that we can’t see these clouds for what they are—a physical manifestation of the violent collision between human civilization and the earth?: Or have we been so accustomed to the bright electric lights that we fail to understand the threatening implication of these clouds / …we fail to understand that it is a glaring sign of the violent clash between human activity and nature?
adjust (to) : to change so as to fit, conform
see : understand
for what they are: in their real light; the real nature of
manifestation: display
Paragraph 9. human’s puzzling response [image-25]
65. Even though it is sometimes hard to see their meaning, we have by now all witnessed surprising experiences: Even though it is sometimes hard to understand the threat of these clouds, we have so far all seen surprising experiences.
66. [surprising e xperience] whether it’s the frequency of days when the temperature exceeds 100 degrees, the new speed with which the sun burns our skin, or the new constancy of public debate over what to do with growing mountains of waste: whether it is the fact that recently there are more hot days when the
temperature is over 100 degrees Fahrenheit (=38 degree Celsius), or the fact the sun burns our skin more quickly in recent times, or the fact that the debate over the way of disposing of the growing amount of waste matter comes up more frequently.
67. But our response to these signals is puzzling: But our reaction to these signals is so baffling that it is difficult to understand.
68. Why haven’t we launched a massive effort to save our environment: Why haven’t we s tarted a large-scale movement to save our environment?
69. To come at the question another way: To approach the question in a different way; to put the question differently
70. Why do some images startle us into immediate action and focus our attention on ways to respond effectively? : Why do some signs so alarm us that we immediately take action and concentrate on ways of dealing with them effectively? some images: e.g. white pollution, (immediate action: stop producing) sandstorm (immediate action: plant grass and trees)
71. And why do other images, though sometimes equally dramatic, produce instead a kind of paralysis, focusing our attention not on ways to respond but rather on some convenient, less painful distraction? : And why do other signs, though sometimes no less striking, only cause a kind of loss and inactivity and we concentrate our attention not on the ways to deal with them but instead, on some other substitutes which are easy to get and less painful?
other images: e.g. gases from cars (distraction: people still want cars, and have an easy and less painful way to deal with this issue, say, it’s a natural cycle, not because of human activities)
Paragraph 10. the importance of organizing our thoughts [image-26 ]
72. it may be helpful to classify them and thus begin to organize our thoughts and feelings so that we may be able to respond appropriately: it may be useful to arrange them into different groups, thus getting our thoughts and feelings straightened out / organized so that we will be able to take the most suitable action.
Paragraph 11. the military system: ―local‖ skirmishes, ―regional‖ battles, and
―strategic‖ conflicts [image-27]
73. theater: scene of operation
e.g. This was the Pacific theatre of World War II.
这里是第二次世界大战的太平洋战区。
lecture theatre 阶梯教室
74. A useful system comes from the military: A useful way of classifying comes from fighting. They are: ―local‖ skirmish, ―regional‖ battles, and ―strategic‖ conflict.
A skirmish is a minor battle
75. be reserved for: If something is reserved for a particular person or purpose, it is kept specially for that person or purpose.
e.g. The garden is reserved for those who work in the museum.
I had a place reserved at the Youth Hostel.
He gave me a look of the sort usually reserved for naughty school children.
76. struggles that can threaten a nation’s survival and must be understood in a global context: struggles that can endanger a nation’s existence and must be viewed against the background of the world.
Paragraph 12. the same case with the images of destruction [image-28]
77. in the same way: in the way of dividing the threats into three categories
78. illegal waste dumping: the disposal of waste in a way that violates the law
79. in nature: in basic quality or character 本质上
e.g. His problem was personal in nature.
These problems are political in nature.
80. Problems like acid rain, the contamination of underground aquifers, and large oil spills are fundamentally regional. Problems like acid rain, the contamination of underground aquifers, and large oil spills basically belong to regional category.
Acid rain（酸雨）[video-6 ]: rain with a high concentration of acids produced by sulfur dioxide (二氧化硫) [video-7 ], nitrogen oxide (氧化氮) [video-8 ], etc. emitted during the combustion （氧化）of fossil fuels; it has a destructive effect on plant and aquatic (水中的) life, buildings, etc.
contamination: to make impure or bad by or as if by mixing in / with impure, dirty or poisonous matter
cf. pollution: Pollution is a term to describe the degrading of the environment in some way—the air we breathe or the water we drink or wash in can be polluted when it is contaminated by some foreign or unwanted material, e.g. engine oil or chemicals in water, smoke, or car exhaust in the air. We talk about air pollution or water pollution—not water contamination but ―pollution‖ is the more common term. Contamination is a more scientific term used to describe a substance contaminating or spoiling something such as an experiment, e.g. the water purity experiment was contaminated by an out side chemical. We would not say ―polluted‖ in this case.
aquifer: an underground layer of porous (多孔的)rock, sand, etc, containing water, into which wells can be sunk.
large oil spill: large-scale leaking of oil from oil tankers
81. the pattern appears to be global: It seems that the problem has acquired a global nature since so many similar things occur at the same time all over the world.
82. because the operation of the global environment is not affect5ed and the survival of civilization is not at stake: because the working of the world environment as a whole has not been affected and the existence of mankind has not been endangered.
at stake: in danger
Paragraph 13. a new class of environmental problems affecting the global ecological system: chlorine [image-29] 80. The 600 percent increase in the amount of chlorine in the atmosphere during the last forty years has taken place not just in those countries producing the chlorofluorocarbons responsible but in the air above every country, above Antarctica, above the North Pole and the Pacific Ocean—all the way from the surface of the earth to the top of the sky: There have been 600 percent increase in the amount of chlorine in the atmosphere during the last forty years not only in those countries which are mainly responsible for the production of CFC but also in the air above every country, above Antarctica, above the North Pole and the Pacific Ocean—all the way from the surface of the earth to the top of the sky. chlorine: 氯
chlorofluorocarbons: CFC 氟里昂[audio-4][video-9 ]:
83. The increased levels of chlorine disrupt the global process by which the earth regulates the amount of ultraviolet radiation from the sun: The increase of the amount of chlorine disturbs the usual way of handling and controlling the amount of ultraviolet radiation the earth receives from the sun.
ultraviolet: (of light) that is beyond the purple end of the range of colours (spectrum) that make up light that can be seen by human beings
ultraviolet rays: 紫外线
ultra-: beyond e.g. ultrared （红外线的）, ultrashort （超短波的）, ultrasonic （超音波的）, ultramodern（极其现代化的）
regulate: adjust; moderate;
84. to the point: to such a degree
Paragraph 14: another strategic threat—global warming [image-30]
85. The concentration of carbon dioxide and other heat-absorbing molecules has increased by almost 25 percent since World War II, posing a worldwide threat to the earth’s ability to regulate the amount of heat from the sun retained in the atmosphere: As a result of the increase of those particles that can take in heat, less heat is released into the high altitude and more heat is kept in the atmosphere than in the past. This will make the climate of the world warmer. concentration: the measure of the amount of a substance constrained in a liquid [术语]浓缩；a lose
Historical Development of Matertials and Technology The common engineering materials include metals, cementing materials, concrete building stones, clay products, insulating materials, timber. Some of them are described here from the stand-point of occurrence, manufacture, properties, methods of testing, and use. The development of materials with improved properties is a vital phase of engineering. Progress in engineering construction has been dependent on the availability of materials of suitable physical properties in large quantities; for example, the development of the modern automobile was critically dependent on availability of high quality alloy steels, and the all-metal airplane was made possible by the development of light weight high-strength alloys. ◆Phase: 相；阶段。 ◆a distinct period or stage in a process of change or forming part of something's development Example： phase two of the development is in progress. ◆第二阶段开发正在进行中。 ◆Vital: 必要的，必不可少的。 ◆it is vital that the system is regularly maintained.这个系统有必要 经常维修。
1 While some studies have suggested that frequent use of cell phones causes increased risk of brain and mouth cancers, others have found no such links. But since cell phones are relatively new and brain cancers grow slowly, many experts are now recommending taking steps to reduce exposure. by bruce stutz 一些研究显示，经常使用手机会增加得脑部和口腔癌症的几率。有的研究却没发现两者之间有什么联系。但是，手机算是个新兴事物，而脑癌发展也缓慢，许多专家还是建议减少使用手机。 2 Does your cell phone increase your risk of brain cancer? Does it affect your skin or your sperm viability? Is it safe for pregnant women or children? Should you keep it in your bag, on your belt, in your pants or shirt pocket? Should you use a hands-free headset? Are present cell phone safety standards strict enough? 手机会增加得脑癌的几率吗？会不会影响皮肤或者精子活性？使用手机对孕妇或孩子安全吗？应该把手机放在哪，包里、衣服口袋，还是挂在腰带上？打电话的时候要用耳机吗？现在的手机安全标准够不够严？ 3 You don’t know? You’re not alone. 你不知道？这很正常。 4 With some 4 to 5 billion cell phones now in use worldwide and hundreds of studies seeking evidence of their health effects published in peer-reviewed journals over the last 10 years, there’s precious little scientific certainty over whether cell phones pose any danger to those using them. For nearly every study that reports an effect, another, just as carefully conducted, finds none. All of which leaves journalists, consumer advocates, regulatory agencies, politicians, industry spokespersons, and cell phone users able to choose and interpret the results they prefer, or ignore the ones they don’t. 如今，全世界共有40-50亿手机正在使用。过去十年里，成百上千的研究也在致力于寻找手机影响健康的证据，并在相关刊物上发表论文。但还没有确凿的证据能证明，使用手机损害健康。几乎没有研究发现手机对健康有不良影响。但这还是没影响到政治家、新闻记者、管理机构、产业发言人、消费者保护团体，还有消费者自己，选择他们喜好的结果去理解，忽略不喜欢的那些。 5 Do you, for instance, cite the studies that report adverse effects on sperm viability and motility, due to exposure to cell phone radiation or the studies that showed no —or mixed —results? 6 Do you cite the 2001 study that found increased incidence of uveal melanoma (a cancer of the eye) among frequent cell phone users, or the 2009 study by the same authors that, in reassessing their data, found no increase? 2001年的研究显示，常用手机的人患葡萄膜黑色素瘤（一种眼内癌症）几率会增大。2009年这些研究员又发表报告称，他们再分析当年的数据时，又不能确
Part I Reading comprehension (40%) 共四篇，其中一篇来自教材，占10%； Passage 6 1. 1) Yes, it is. 2) Once the technology had evolved, it became possible. It is just a matter of time. 3) The faster you go, the slower time seems to move for you with respect to everyone else. This concept is known as “time dilation.” 4) travel at the speed of light; 5) If your speed finally reaches the speed of light then time actually stands still, exceed the speed of light and its thought that time will start to flow backward. 6) An effect of Relativity is that the faster you go, the heavier you become and as you reach the speed of light, you become infinitely heavy. 7) The technique is called “quantum tunneling”. It is used by electrons orbiting around atoms to instantly move from point A to point B without passing through the space between. 8)It is actually only technology stopping us from doing it. 2. 1) 即使如我面前的杯子这么普通的东西也可以说某种程度上掌握了时间旅行。它在桌子上放着，看似无所事事，然而实际上正在穿越时空，无情地，它的速度是每天走一天。 2）如果我跑到这咖啡店的速度接近光速，当我坐下来时，我的年龄小于我周围的人。实际上，我已经走到他们的未来。 3) 剩下的就是当宇宙倒退时，以这个速度飞行，在适当的时候减速，然后在1973年7月突然出现，那是有史以来最伟大的时刻——我出生啦。 Passage 7 1. 1)By altering the function of one gene, the life span of a species of roundworm could be
United 1 材料科学与工程 材料在我们的文化中比我们认识到的还要根深蒂固。如交通、房子、衣物，通讯、娱乐和食物的生产，实际上，我们日常生活中的每一部分都或多或少地受到材料的影响。历史上社会的发展、先进与那些能满足社会需要的材料的生产及操作能力密切相关。实际上，早期的文明就以材料的发展程度来命名，如石器时代，铜器时代。早期人们能得到的只有一些很有限的天然材料，如石头、木材、粘土等。渐渐地，他们通过技术来生产优于自然材料的新材料，这些新材料包括陶器和金属。进一步地，人们发现材料的性质可以通过加热或加入其他物质来改变。在这点上，材料的应用完全是一个选择的过程。也就是说，在一系列非常有限的材料中，根据材料的优点选择一种最适合某种应用的材料。直到最近，科学家才终于了解材料的结构要素与其特性之间的关系。这个大约是过去的 60 年中获得的认识使得材料的性质研究成为时髦。因此，成千上万的材料通过其特殊的性质得以发展来满足我们现代及复杂的社会需要。很多使我们生活舒适的技术的发展与适宜材料的获得密切相关。一种材料的先进程度通常是一种技术进步的先兆。比如，没有便宜的钢制品或其他替代品就没有汽车。在现代，复杂的电子器件取决于所谓的半导体零件. 材料科学与工程有时把材料科学与工程细分成材料科学和材料工程学科是有用的。严格地说，材料科学涉及材料到研究材料的结构和性质的关系。相反，材料工程是根据材料的结构和性质的关系来设计或操纵材料的结构以求制造出一系列可预定的性质。从功能方面来说，材料科学家的作用是发展或合成新的材料，而材料工程师是利用已有的材料创造新的产品或体系，和/或发展材料加工新技术。多数材料专业的本科毕业生被同时训练成材料科学家和材料工程师。“structure”一词是个模糊的术语值得解释。简单地说，材料的结构通常与其内在成分的排列有关。原子内的结构包括介于单个原子间的电子和原子核的相互作用。在原子水平上，结构包括原子或分子与其他相关的原子或分子的组织。在更大的结构领域上，其包括大的原子团，这些原子团通常聚集在一起，称为“微观”结构，意思是可以使用某种显微镜直接观察得到的结构。最后，结构单元可以通过肉眼看到的称为宏观结构。 “Property”一词的概念值得详细阐述。在使用中，所有材料对外部的刺激都表现出某种反应。比如，材料受到力作用会引起形变，或者抛光金属表面会反射光。材料的特征取决于其对外部刺激的反应程度。通常，材料的性质与其形状及大小无关。实际上，所有固体材料的重要性质可以概括分为六类：机械、电学、热学、磁学、光学和腐蚀性。对于每一种性质，其都有一种对特定刺激引起反应的能 力。如机械性能与施加压力引起的形变有关，包括弹性和强度。对于电性能，如电导性和介电系数，特定的刺激物是电场。固体的热学行为则可用热容和热导率来表示。磁学性质
Why We're Fat 1 So why is obesity happening? The obvious, clichéd-but-true answer is that we eat too much high-calorie food and don't burn it off with enough exercise. If only we had more willpower, the problem would go away. But it isn't that easy. 为什么会有肥胖症？一个明显、老生常谈但又真实的答案就是我们吃太多高热量食物并且没有进行足够的运动消耗它。要是我们的意志力更强大，这个问题便迎刃而解了。但是，问题并不是那么简单。 2 When warned about the dangers of overeating, we get briefly spooked and try to do better. Then we're offered a plateful of pancakes smothered in maple syrup, our appetite overpowers our reason, and before we know it, we're at it again. Just why is appetite such a powerful driver of behavior, and, more important, how can we tame it? 当我们被警告说吃得太多的时候，一时总会被吓倒并努力做好一些。然后一碟涂满槭糖浆的煎饼摆在面前，我们的食欲战胜了我们的理智，等到我们意识到它的时候，我们又重蹈覆辙了。到底为什么食欲具有如此强大的推动力？更重要的是，我们怎么才能够控制它？ 3 Within the past few years, science has linked our ravenous appetites to genes and hormones. Among the hormones that fuel these urges are ghrelin and leptin, known as the "hunger hormones." Ghrelin is produced mostly by cells in the stomach lining. Its job is to make you feel hungry by affecting the hypothalamus, which governs metabolism. Ghrelin levels rise in dieters who lose weight and then try to keep it off. It's almost as if their bodies are trying to regain the lost fat. This is one reason why it's hard to lose weight and maintain the loss. 近几年来，科学将我们迫不及待要吃的食欲跟基因和激素联系起来。激起这些强烈的欲望的激素有胃促生长素和消瘦素，也被称作“饥饿激素”。胃促生长素主要由胃保护层的细胞产生。它的职责是影响控制新陈代谢的下丘脑，让你感到饥饿。当节食者减肥并且努力维持减肥效果，他的胃促生长素水平就会升高。就像他们的身体要试图恢复失去的脂肪。这是为什么很难减肥并维持减肥效果的原因之一。 4 Leptin turns your appetite off and is made by fat cells. Low leptin levels increase your appetite and signal your body to store more fat. High leptin levels relay the opposite signal. Many obese people have developed a resistance to the appetite-suppressing effects of leptin and never feel satisfied, no matter how much they eat. Basically, your body uses these hormones to help you stay at your weight and keep you from losing fat —which is another reason why dieting can be so difficult. 消瘦素消除你的食欲，它来自脂肪细胞。低消瘦素水平增加你的食欲并通知你的身体储存更多的脂肪。高消瘦素水平传递相反的信号。很多肥胖的人已经形成了一种对消瘦素抑制食欲效应的抵抗，不管他们吃多少也从不感到满足。从根本上说，你的身体利用这些激素帮助你保持现在的体重，不让你的脂肪流走——这是节食如此之难的另外一个原因。
第一单元环境 大规模研究发现：地球的“健康”每况愈下有史以来对地球进行的最大规模的科学分析表明，地球上的许多生态系统都达不到标准。 由联合国主持的《千年生态系统评估综合报告》指出，由于不可持续的使用，地球上将近三分之二的用来维持生命的生态系统已经遭到破坏，其中包括干净的水源、纯净的空气，以及稳定的气候。 以上大部分的破坏都是人类在过去的半个世纪里造成的。据报告分析，随着人类对食物、淡水、木材、纤维以及燃料等资源的需求日趋激增，环境发生了极大的变化，引发了诸如滥伐森林、化学污染等问题。因此，该报告的作者警告说，照此下去，本已岌岌可危的生态环境将会在21世纪的上半叶急剧恶化。 这项历史性的研究由来自世界95个国家的政府部门以及民间组织的1,300多位科学家共同完成。四年来，他们考察了地球上许多生物的生长环境、物种以及将他们联系起来的生态体系。联合国环境规划署对该报告进行了编辑整理并于昨天在中国北京公布了研究结果。 在公布该报告的新闻发布会上，联合国秘书长科菲·安南指出：“只有了解环境及其运作过程，我们才能制定出必要的决策加以保护。”他还说，“只有珍惜所有宝贵的自然资源和人类资源，我们才有希望去建设一个可持续发展的未来。” 对社会经济的影响 该报告对自然界的大部分生物多样性持悲观态度，地球上可能有10%—30%的哺乳动物，鸟类以及两栖动物濒临灭绝。 这次大规模生态调查是根据安南的《千年发展目标》展开的，该发展目标是由联合国发起的，旨在2015年之前大幅度缓解饥饿与极度贫困等社会经济问题。 总部位于内罗毕的联合国环境规划署执行主席克劳斯·托普弗说：“从某些方面来说，《千年生态系统评估综合报告》让我们首次认识到生态系统服务功能的经济价值，并使我们对尊重和保护地球生命维护系统有了新的见解。” 目前由于人类社会对地球环境的开发利用，食物供应不断增加，然而增长的速度仍然太慢，难以完成联合国制定的在2015年前消除全球一半饥饿的目标。 报告还说，过度使用生态系统的负面影响还包括渔业的衰退，含有大量沉积物的河口周围近海“死亡区”的出现，水质的变化以及不可预测的区域性气候等。 此外，森林的滥伐和其他生态系统的巨大改变也加剧了诸如疟疾、霍乱等疾病的传播，并使已有传染病分化出新的类别。 根据该报告，水资源体系的变化会增加毁灭性洪灾的爆发频率和程度。在20世纪90年代，洪灾造成的死亡人数超过10万，损失约2,430亿美元。
1.2 总线互连 总线是连接两个或多个设备的通信通路。总线的关键特征是，它是一条共享传输介质。多个设备连接到总线上，任一个设备发出的信号可以为其他所有连接到总线上的设备所接收。如果两个设备同时传送，它们的信号将会重叠，引起混淆。因此，一次只能有一个设备成功地（利用总线）发送数据。 典型的情况是，总线由多条通信通路或线路组成，每条线(路)能够传送代表二进制1和0的信号。一段时间里，一条线能传送一串二进制数字。总线的几条线放在一起能同时并行传送二进制数字。例如, 一个8位的数据能在8条总线线上传送。 计算机系统包含有多种不同的总线，它们在计算机系统层次结构的各个层次提供部件之间的通路。连接主要计算机部件(处理机, 存储器, I/O)的总线称为系统总线。系统总线通常由50~100条分立的(导)线组成。每条线被赋予一个特定的含义或功能。虽然有许多不同的总线设计，但任何总线上的线都可以分成三个功能组：数据线、地址线和控制线。此外可能还有为连接的模块提供电源的电源线。 数据线提供系统模块间传送数据的路径，这些线组合在一起称为数据总线。典型的数据总线包含8、16或32根线，线的数量称为数据总线的宽度。因为每条线每次传送1位，所以线的数目决定了每次能同时传送多少位。数据总线的宽度是决定系统总体性能的关键因素。 地址线用于指定数据总线上数据的来源和去向。例如，如果处理机希望从存储器中读一个字的数据，它将所需要字的地址放在地址线上。显然，地址总线的宽度决定了系统最大可能的存储器容量。 控制线用来控制对数据线和地址线的访问和使用。由于数据线和地址线被所有部件共享，因此必须用一种方法来控制它们的使用。控制信号在系统模块之间传送命令和定时信息。定时信息指定了数据和地址信息的有效性，命令信号指定了要执行的操作。 大多数计算机系统使用多总线，这些总线通常设计成层次结构。图1.3显示了一个典型的高性能体系结构。一条局部总线把处理机连接到高速缓存控制器，而高速缓存控制器又连接到支持主存储器的系统总线上。高速缓存控制器集成到连接高速总线的桥中。这一总线支持连接到：高速LAN、视频和图形工作站控制器，以及包括SCSI 和FireWire的局部外设总线的接口控制器。低速设备仍然由分开的扩充总线支持，用一个接口来缓冲该扩充总线和高速总线之间的通信流量。 PCI 外部设备互连是流行的高带宽的、独立于处理机的总线，它能够作为中间层或外围设备总线。当前的标准允许在66MHz频率下使用多达64根数据线，其原始传输速率为528MB/s, 或4.224Gbps。PCI被设计成支持各种各样基于微处理机的配置，包括单处理机和多处理机的系统。因此，它提供了一组通用的功能。PCI使用同步时序以及集中式仲裁方案。 在多处理机系统中，一个或多个PCI配置可通过桥接器连接到处理机的系统总线上。系统总线只支持处理机/高速缓存单元、主存储器以及PCI桥接器。使用桥接器使得PCI独立于处理机速度，又提供快速接收和传送数据的能力。 2.1 光存储介质：高密度存储器 2.1.1 光盘 光盘技术最终可能使磁盘和磁带存储淘汰。用这种技术，磁存储器所用的读/写头被两束激光代替。一束激光通过在光盘上刻制微小的凹点，对记录表面进行写；而另一束激光用来从光敏感的记录表面读取数据。由于光束容易被偏转到光盘上所需要的位置，所以不需要存取臂。 对用户而言，光盘正成为最有吸引力的选择。它们(光盘)对环境变化不太敏感，并且它们以每兆字节比磁盘低得多的存储器价格提供更多的直接存取存储器。光盘技术仍在出现，并且还需要稳定；然而，目前有三种主要类型的光盘。它们是CD-ROM、WORM盘和磁光盘。 CD-ROM 1980年引入的，非常成功的CD，或紧密盘是设计来提高音乐的录音重放质量的光盘。为了制作一张CD，把音乐的模拟声音转换成等价的数字声音，并且存储在一张4.72英寸的光盘上。在每张光盘上可以用数字格式（用20亿数字位）记录74分钟的音乐。因为它的巨大存储容量，计算机工业的企业家们立刻认
核电与核辐射 1986 年4 月26 日，切尔诺贝利核电站的一个反应堆发生爆炸，将相当于400 颗广岛原子弹的放射性尘降物散布到整个北半球。在此之前，科学家对辐射对植物和野生动物的影响 几乎一无所知。这场灾难创造了一个活生生的实验室，尤其是在这个被称为禁区的1100 平方英里的区域。 1994 年，德州理工大学生物学教授罗纳德·切瑟和罗伯特·贝克是首批获准完全进入该区域的美国科学家之一。“我们抓了一群田鼠，它们看起来和野草一样健康。我们对此非 常着迷。”贝克回忆说。当Baker 和Chesser 对田鼠的DNA 进行测序时，他们没有发现 异常的突变率。他们还注意到狼、猞猁和其他曾经稀有的物种在这片区域游荡，仿佛这里 是原子野生动物保护区。2003 年由一组联合国机构建立的切尔诺贝利论坛发表了声明一份关于灾难20 周年的报告证实了这一观点，称“环境条件对该地区的生物群落产生了积极 影响”，将其转变为“一个独特的生物多样性保护区”。 五年前，贝克和切塞尔在这片区域搜寻田鼠。Mousseau 到切尔诺贝利去数鸟，发现了与之相矛盾的证据。穆萨乌是南卡罗莱纳大学的生物学教授，他的合作者安德斯·佩普·穆 勒现在是巴黎南方大学生态、系统学和进化实验室的研究主任。他们发现该地区家燕的数 量要少得多，而那些存活下来的家燕则遭受着寿命缩短、(雄性)生育能力下降、大脑变小、肿瘤、部分白化病(一种基因突变)以及白内障发病率更高的痛苦。在过去13 年发表的60 多篇论文中，Mousseau 和Moller 指出，暴露在低水平辐射下对该区域的整个生物圈产生 了负面影响，从微生物到哺乳动物，从昆虫到鸟类。 包括贝克在内的批评人士对穆萨和穆勒持批评态度。贝克在2006 年与切塞尔合著的《美国科学家》(American Scientist)文章中指出，该区域“实际上已成为一个保护区”，穆萨和穆勒的“令人难以置信的结论只得到了间接证据的支持”。 我们所知道的关于电离辐射对健康影响的几乎所有信息都来自于一项正在进行的对原子弹幸存者的研究，该研究被称为寿命研究，简称LSS。辐射暴露的安全标准基于LSS。然而，LSS 留下了关于低剂量辐射影响的大问题没有得到解答。大多数科学家都同意，没有所谓 的“安全”辐射剂量，无论剂量有多小。小剂量是我们最不了解的。LSS 并没有告诉我们多 少低于100 毫西弗(mSv)的剂量。例如，引起基因突变需要多少辐射，这些突变是可遗传 的吗?辐射诱发的疾病(如癌症)的机制和遗传生物标记物是什么? 三重危机2011年 3月福岛第一核电站创建另一个生活摩梭实验室和穆勒可以研究低 剂量的辐射,复制他们的切尔诺贝利核事故研究和允许他们“更高的信心,影响我们看到有关辐射,而不是其他因素,“摩梭说。福岛310平方英里的隔离区比切尔诺贝利小，但在其他方面 是一样的。这两个区域都包括被遗弃的农田、森林和城市地区，在这些地区，辐射水平在 短距离内变化数量级。而且几乎可以肯定，他们进入福岛的速度比科学家进入苏联控制的 切尔诺贝利的速度还要快。简而言之，福岛事件提供了一个解决争议的机会。 福岛核事故发生后的几个月里，穆萨乌和莫勒就开始在这座正在冒烟的核电站以西受污染的山林里清点鸟类数量，但他们无法进入这个区域，亲眼看看家燕的情况。最后，在2013 年6 月，穆萨乌是首批获准完全进入福岛禁区的科学家之一。 对辐射的敏感度在生物和同一物种的个体之间有很大的差异，这是重要的原因之一，不要从蝴蝶推断到家燕或从田鼠推断到人类。蝴蝶对辐射特别敏感，Mousseau 说。2012年8 月，在线期刊《科学报告》(Scientific Report)发表了一篇论文，研究福岛核泄漏对淡草蓝 蝶的影响。冲绳县琉球大学的生物学教授大木若二(Joji Otaki)透露，在这种不雅行为发生两个月后，在福岛附近采集的蝴蝶出现了翅膀、腿和眼睛畸形的情况。Mousseau 和Moller 对切尔诺贝利和福岛昆虫的调查显示，蝴蝶作为一个群体数量急剧下降。但御宅族
实用法律英语中英对照版 ——民事 civil ——民事 civil affairs;affairs relating to civil law ——民事上的占有 civil possesion ——民事上的没收 civil forfeiture ——民事上诉 civil appeal ——民事主体 civil subject ——民事法律关系 civil legal relationship ——民事活动 activity relating to civil law ——民事纠纷 civil dispute ——民事客体 civil object ——民事原告 civil plaintiff ——民事被告 civil defendant ——民事指控 civil charge ——民事案件 civil case ——民事过失 civil negligence ——民事责任事故 accident involving civil liability ——民事补偿 civil remedy ——民事诉讼 civil action ——民事损害 civil injury
——民事债务 civil debt ——民事管辖 civil jurisdiction ——民事制裁 civil sanction ——民事审判 civil trial ——民事调解 civil mediation ——民事罚款 civil penalty ——民事权利争议 dispute concerning private rights ——民事权利剥夺 deprived of private rights ——民事权利请求 civil claim ——民事权利变更 alternation of private right ——民政 civil administraion ——民事权利与责任 civil right and liability ——民事权利 civil right ——人身权利 jura personarum; rights of the person ——人格权 right of personality ——上诉权 right of appeal ——不受时效限制权 imprescriptible right ——立遗嘱权 right to make a will ——合法权利 legal right ——共有权 communal tenure
School of chemical engineering and pharmaceutical test tubes 试管test tube holder试管夹test tube brush 试管刷test tube rack试管架 beaker烧杯stirring搅拌棒thermometer温度计boiling flask长颈烧瓶Florence flask平底烧瓶 flask,round bottom,two-neck boiling flask,three-neck conical flask锥形瓶wide-mouth bottle广口瓶graduated cylinder量筒gas measuring tube气体检测管volumetric flask容量瓶transfer pipette移液管Geiser burette(stopcock)酸式滴定管funnel漏斗Mohr burette(with pinchcock)碱式滴定管 watch glass表面皿evaporating dish蒸发皿ground joint磨口连接Petri dish有盖培养皿 desiccators干燥皿 long-stem funnel长颈漏斗filter funnel过滤漏斗 Büchner funnel瓷漏斗separatory funnel分液漏斗 Hirsh funnel赫尔什漏斗filter flask 吸滤瓶Thiele melting point tube蒂勒熔点管 plastic squeez e bottle塑料洗瓶 medicine dropper药用滴管rubber pipette bulb 吸球microspatula微型压舌板pipet吸量管mortar and pestle研体及研钵filter paper滤纸Bunsen burner煤气灯burette stand滴定管架support ring支撑环 ring stand环架distilling head蒸馏头 side-arm distillation flask侧臂蒸馏烧瓶air condenser空气冷凝器centrifuge tube离心管 fractionating column精(分)馏管 Graham condenser蛇形冷凝器 crucible坩埚crucible tongs坩埚钳beaker tong烧杯钳economy extension clamp经济扩展夹extension clamp牵引夹utility clamp铁试管夹hose clamp软管夹 burette clamp pinchcock;pinch clamp弹簧夹 screw clamp 螺丝钳 ring clamp 环形夹goggles护目镜stopcock活塞wire gauze铁丝网analytical balance分析天平 分析化学 absolute error绝对误差accuracy准确度assay化验analyte(被)分析物calibration校准constituent成分coefficient of variation变异系数confidence level置信水平detection limit检出限determination测定estimation 估算 equivalent point等当点gross error总误差impurity杂质indicator指示剂interference干扰internal standard内标 level of significance显著性水平 limit of quantitation定量限masking掩蔽matrix基体precision精确度 primary standard原始标准物purity纯度qualitative analysis定性分析 quantitative analysis定量分析random error偶然误差reagent试剂 relative error相对误差robustness耐用性sample样品relative standard deviation相对标准偏差 selectivity选择性sensitivity灵敏度specificity专属性titration滴定significant figure有效数字solubility product溶度积 1
Unit 1 Genetically modified foods -- Feed the World? If you want to spark a heated debate at a dinner party, bring up the topic of genetically modified foods. For many people, the concept of genetically altered, high-tech crop production raises all kinds of environmental, health, safety and ethical questions. Particularly in countries with long agrarian traditions -- and vocal green lobbies -- the idea seems against nature. 如果你想在某次晚宴上挑起一场激烈的争论，那就提出转基因食品的话题吧。对许多人来说，高科技的转基因作物生产的概念会带来诸如环境、健康、安全和伦理等方面的各种问题。特别是在有悠久的农业生产传统和主张环保的游说集团的国家里，转基因食品的主意似乎有悖自然。 In fact, genetically modified foods are already very much a part of our lives. A third of the corn and more than half the soybeans and cotton grown in the US last year were the product of biotechnology, according to the Department of Agriculture. More than 65 million acres of genetically modified crops will be planted in the US this year. The genetic is out of the bottle. 事实上，转基因食品已经成为我们生活重要的一部分。根据农业部的统计，美国去年所种植玉米的1／3，大豆和棉花的一半以上都是生物技术的产物。今年，美国将种植6500多万英亩的转基因作物。基因妖怪已经从瓶子里跑出来了。 Yet there are clearly some very real issues that need to be resolved. Like any new product entering the food chain, genetically modified foods must be subjected to rigorous testing. In wealthy countries, the debate about biotech is tempered by the fact that we have a rich array of foods to choose from -- and a supply that far exceeds our needs. In developing countries desperate to feed fast-growing and underfed populations; the issue is simpler and much more urgent: Do the benefits of biotech outweigh the risks? 但是，显然还有一些非常现实的问题需要解决。就像任何一种要进入食物链的新食品一样，转基因食品必须经过严格的检验。在富裕的国家里，由于有大量丰富的食品可供选择，而且供应远远超过需求，所以关于生物技术的争论相对缓和一些。在迫切想要养活其迅速增长而又吃不饱的人口的发展中国家，问题比较简单，也更加紧迫：生物技术的好处是否大于风险呢? The statistics on population growth and hunger are disturbing. Last year the world's population reached 6 billion. And by 2050, the UN estimates, it will probably near 9 billion. Almost all that growth will occur in developing countries. At the same time, the world's available cultivable land per person is declining. Arable land has
第一课美国法律制度介绍 第一部分特征与特点 美国既是一个非常新的国家也是一个非常老的国家。与许多别的国家相比它是一个新的国家。同时，它还因新人口成分和新州的加入而持续更新，在此意义上，它也是新国家。但是在其它的意义上它是老国家。它是最老的“新”国家——第一个由旧大陆殖民地脱胎而出的国家。它拥有最古老的成文宪法、最古老的持续的联邦体制以及最古老的民族自治实践。 美国的年轻（性）有一个很有意思的特点就是它的历史肇始于印刷机发明之后。因此它的整个历史都得以记录下来：确实可以很有把握地说，任何其它国家都没有像美国这样全面的历史记录，因为像在意大利、法国或者英国过去的传说中湮没的那样的事件在美国都成了有文字记载的历史之一部分。而且其记录不仅全面，还非常浩繁。不仅包括这个国家自1776年以来的殖民时期的记录，还有当前五十个州以及各州和联邦（nation）之间错综复杂的关系网络的历史记录。因此，据一个非常简单的例子，美国最高法院判例汇编有大约350卷，而一些州的判例汇编也几乎有同样多的卷数：想研究美国法律史的读者要面对的是超过5000巨卷的司法案例。 我们不能说一个文件或几个文件就能揭示出一国人民或其政府的特性。但如果横跨一百多年的千百万个文件敲出始终如一的音调，我们就有理由说这就是其主调。当千百万个文件都以同样的方式去解决同样的中心问题，我们就有理由从中得出可以被称为国民特定的确定结论。 第二部分普通法和衡平法 同英国一样，美国法律制度从方法论上来说主要是一种判例法制度。许多私法领域仍然主要是由判例法构成，广泛而不断增长的制定法一直受制于有约束力的（解释制定法的）判例法。因此，判例法方法的知识以及使用判例法的技巧对于理解美国法律和法律方法是极其重要的。 从历史的角度来看，普通法就是由英国皇家法院的巡回法官的判决所得出的普通的一般法——优于地方法。采纳或执行某项诉讼请求是以存在法院令状这种特殊形式的诉为前提的，而这就使最初的普通法表现为由类似于古罗马法的“诉”所构成的体系。如果存在令状（于1227年），诉讼请求就可以被采纳或执行；没有法院令状（为前提）的诉讼请求就没有追索权，因而该诉讼请求也不存在。“牛津条例”（1285年）禁止创设除了“个案令状”之外的新令状，这种“个案令状”使该制度变得较为灵活了，而且导致了后来合同和侵权法的发展。 对于诉的形式的严格限制及由此产生的对追索权的限制导致了衡平法和衡平判例法的发展。“衡平”的一般意义就是寻求“公平”，即公平且善良地裁决，它最初是由国王，后来由作为“国王良知守护人”的大法官颁行，以便在艰难的案件中提供救济。但是到了十四世纪，衡平法和衡平判例法发展成了一个独立的法律制度和与一般的普通法法院一争高下的司法系统（衡平法院）。其规则和格言变得非常固定而且在某种程度上不像在其它法律制度中一样灵活。衡平法的特点有：以特定履行（或实际履行）的方式提供救济（与普通法提供补偿性损害赔偿金的救济方式形成对照）；强制令（为或者不为某项具体行为的临时或者最终法令）；渗透了整个法律制度并且能在许多场合下揭示现代法律概念的起源的所谓的衡平法格言的发展。不过，一般都是只有在普通法救济不充分时，才会出现衡平法救济。比如，优于普通法损害赔偿金被认为是不充分的，这是因为考虑到不动产所具有的唯一性，这些赔偿金无法补偿不动产购买人（的损失），就可能判以特定履行购买不动产。 与普通法一样，衡平法通过司法接纳或通过明确的制定法条款，成了美国法律的一部分。目前，这两个法律制度在许多美国司法管辖区中得以融合（始于1848年的纽约），因而，在这些司法管辖区以及联邦的实践中只存在一种形式的民事诉讼。只有为数很少的州还保留着单独的衡平法院。尽管如此，提及这一历史演变仍然是很重要的，因为它一方面解释了许多当代法律概念（如财产法中的所有权分割）的起源和意义，另一方面，它仍然与做出某些裁决有一定的关联，比如是否有权获得陪审团的审理（这仅发生与普通法的讼案中，在其它案件中仅由法官审理）。另外，这种区别将决定“通常的”普通法赔偿金救济是否适用或者是否可以使用“特别的”衡平法特定履行救济。 “判例法”代表了整个的法官造法体系，而且在现代还包括了普通法和衡平法先例。在不准确的和令人迷惑的用法中，“普通法”和“判例法”这两个术语通常被当作同义词来使用，在这里，“普通法”这个术语一般代表着法官制定的法，以示区别制定法。“判例法”总是代表着法官制定的法律，而“普通法”则相对来说，根据想表达的意思不同，要么代表普通法主题事项（即具体问题）上法官制定的法律，要么在更广范围内指所有法官制定的法律。 第二课法律职业 第一部分律师协会 法律职业的规范主要是各州的事务，每一各州对于执业许可都有其自己的要求。大多数州都要求三年的学业和法律学位。各州自行管理本州申请律师资格的书面考试。不过，几乎所有的州都利用“多州律师资格考试”，这是一种长达一天的多项选择测试，在这项考试之外，各州还会再增加一次主要是关于其本州法律的时长一天的论文考试。大多数申请人都可以通过第一次考试，而且许多失败者都会在下一次考试中通过。每年有四万多人通过这些考试，在经过人品调查之后，他们便可获准在相应的州执业许可。在获得许可之前或之后都不要求实习。到各联邦法院执业的许可规则互不相同，但一般来讲，那些获准在州最高法院执业的律师在办理一些无关紧要的手续之后即可获准在联邦法院执业。 律师执业范围通常仅限于一个地区，因为尽管律师可以代表当事人到其它地区办理事务，但是一个人只能在其获得许可的州内执业。人们习惯雇用本州的律师办理其它洲的事务。但是，只要一个人已经在其获得职业资格的州执业达一定时间（通常是五年），那么他移居到另外一个州时通常无需考试便可获得执业许可。 律师不仅可以从事法律事务，还允许从事任何其他公民能从事的事务。执业律师在企业客户的董事会中工作、从事商业或者积极参与公共事务都是很平常的事情。律师即使在成为法官、政府或者私人企业集团的雇员或者法律教师之后仍然是律师协会的会员，他们可以辞掉这些其它事务，回头开始私人执业。为了在工商业中担任重要的执行职务而放弃执业的律师人数相对较少。这一职业中的流动性和公共责任感的一个例证是哈兰·菲斯克的职业生涯，他曾多次成为一名纽约州律师、一名教授和哥伦比亚法学院院长、美国总检察长和美国最高法院首席大法官。 律师并不按照职责进行正式的划分。在英国对诉讼律师和非诉律师的区分并没有移植到美国，既不存在拥有特别或者专有出庭权的职业群体，也没有专门制作法律文书的职业群体。美国律师的业务范围包括出庭辩护、咨询和起草文书。另外，在被广泛地成为“法律执业”的范围之内，律师的业务范围是专有性的，不对其他人开放。在出庭辩护领域，这种规则非常清楚：任何个人都可以代表其自己出庭，但除了一些基层法院之外，只有律师可以代表他人出庭。不过，律师不得代表他人参与一些行政机关设立的具有司法性质的正式程序当中。在咨询和起草法律文书领域的界限并不是太清晰，比如在在联邦所得税领域的法律执业和会计执业之间就是如此。但是，纽约最高法院的一个裁决表明了大多数美国法院的严格标准，该裁决认为，一个获准在外国执业单位获准在纽约执业的律师不得在纽约对客户提供法律咨询，即使该意见仅限于该律师获准执业的该外国的法律。但是，一个外国律师可能获准在一个州执业，而且无需获得许可便可以以一个外国法律顾问的身份向美国律师提供法律咨询。 1