1 Hello. My name is Stephen Hawking. Physicist, cosmologist and something of a dreamer. Although I cannot move and I have to speak through a computer, in my mind I am free. Free to explore the universe and ask the big questions, such as: is time travel possible? Can we open a portal to the past or find a shortcut to the future? Can we ultimately use the laws of nature to become masters of time itself?
大家好，我是斯蒂芬-霍金，是物理学家、宇宙学家及梦想家，尽管身体不能活动，只能通过电脑与大家交流，但从内心中我是自由的，自由地探索宇宙，思考以下重大问题：时间旅行是否可行？能否打开一个回到过去的通道，或找到通向未来的捷径？我们最终能否利用自然规律成为掌控时间的主人？
2 To see how this might be possible, we need to look at time as physicists do - at the fourth dimension. It's not as hard as it sounds. Every attentive schoolchild knows that all physical objects, even me in my chair, exist in three dimensions. Everything has a width and a height and a length.
为了让这一切从虚幻变成现实，我们应以物理学家的角度来重新审视时间——即第四维。这个问题没有听上去那么晦涩难懂。每个好学的孩子都知道，任何物体都以三维形式存在，包括坐在轮椅上的我。一切物体都有宽度、高度和长度。
3 But there is another kind of length, a length in time. While a human may survive for 80 years, the stones at Stonehenge, for instance, have stood around for thousands of years. And the solar system will last for billions of years. Everything has a length in time as well as space. Travelling in time means travelling through this fourth dimension.
此外，还有一种长度——时间的长度。例如，虽然一个人可能活了80岁，但巨石阵的石头却数千年屹立不倒。太阳系的运行将持续数十亿年。一切物体都有时间以及空间的长度。时间旅行意味着我们要经过第四维。
4 To see what that means, let's imagine we're doing a bit of normal, everyday car travel. Drive in a straight line and you're travelling in one dimension. Turn right or left and you add the second dimension. Drive up or down a twisty mountain road and that adds height, so that's travelling in all three dimensions. But how on Earth do we travel in time? How do we find a path through the fourth dimension?
要想搞明白这一点，我们可以想象正在从事一种日常活动，比如开车。开车沿直线行驶，是在一维中旅行。向左转或是向右转，则是二维旅行。驱车上下山路意味着又多增加了高度，所以是在三维空间内。那么我们怎样才能实现时间旅行？怎样才能发现穿越第四维的通道呢？
5 Let's indulge in a little science fiction for a moment. Time travel movies often feature a vast, energy-hungry machine. The machine creates a path through the fourth dimension, a tunnel through time. A time traveller, a brave, perhaps foolhardy individual, prepared for who knows what, steps into the time tunnel and emerges who knows when. The concept may be far-fetched, and the reality may be very different
from this, but the idea itself is not so crazy.
让我们暂时从科幻电影中寻找答案吧。在此类电影中，通常会有一台巨大而高能耗的时间机器，这台机器产生通往第四维的通道——“时光隧道”。时光旅行者——勇敢但可能有些鲁莽的人，做好我们大家所知道的准备，然后走进时光隧道，来到一个他们想要到达的时间里。这一概念可能有些牵强，事实可能与之存在着天壤之别，但该想法本身不是那么的疯狂。
6 Physicists have been thinking about tunnels in time too, but we come at it from a different angle. We wonder if portals to the past or the future could ever be possible within the laws of nature. As it turns out, we think they are. What's more, we've even given them a name: wormholes. The truth is that wormholes are all around us, only they're too small to see. Wormholes are very tiny. They occur in nooks and crannies in space and time. You might find it a tough concept, but stay with me.
物理学家们也在思考时光隧道，但我们的角度不同。我们想搞清过去或未来的通道是否存在于自然规律中？事实证明，我们认为确实是这样的。而且，我们还给它们起了一个名字：虫洞。其实，虫洞无处不在，只是因为太小，我们肉眼看不到罢了。虫洞非常小，存在于时空的隐蔽处和缝隙里。你或许认为这是一个难以理解的概念，请耐心听我继续解释吧。
7 Nothing is flat or solid. If you look closely enough at anything you'll find holes and wrinkles in it. It's a basic physical principle, and it even applies to time. Even something as smooth as a pool ball has tiny crevices, wrinkles and voids. Now it's easy to show that this is true in the first three dimensions. But trust me, it's also true of the fourth dimension. There are tiny crevices, wrinkles and voids in time. Down at the smallest of scales, smaller even than molecules, smaller than atoms, we get to a place called the quantum foam. This is where wormholes exist. Tiny tunnels or shortcuts through space and time constantly form, disappear, and reform within this quantum world. And they actually link two separate places and two different times.
任何物质都不是平整无暇和实心的，如果仔细观察，会发现它们上面都存在小孔和裂缝，这是一个基本的物理原理，同样适用于时间。即便是像台球一样的东西，上面也有裂缝、褶皱或空洞。现在容易说明这种情况也存在于第一个三维中。相信我，这一原理同样适用于第四维。时间也存在许多微小的裂缝、褶皱和空洞。在最小的刻度下——比分子甚至原子都小，我们来到一个称为量子泡沫(quantum foam)的地方，这是虫洞存在之处。时空中的微小隧道或捷径不停地在这个量子世界中形成、消失和重新形成。它们可以连接两个隔离的空间以及两个不同的时间。
8 Unfortunately, these real-life time tunnels are just a billion-trillion-trillionths of a centimetre across. Way too small for a human to pass through - but here's where the notion of wormhole time machines is leading. Some scientists think it may be possible to capture a wormhole and enlarge it many trillions of times to make it big enough for a human or even a spaceship to enter.
不幸的是，现实生活中这种时光隧道非常狭小，即使发现了它们，我们也不能从这个缝隙穿过——可这正是“虫洞时间机器”概念的前进方向。部分科学家认为，
或许有一天捕捉到一个虫洞，将它放大数万亿倍，令其足够的大，能让人甚至飞船进入。
9 Given enough power and advanced technology, perhaps a giant wormhole could even be constructed in space. I'm not saying it can be done, but if it could be, it would be a truly remarkable device. One end could be here near Earth, and the other far, far away, near some distant planet.
如果我们拥有足够的能量和先进的技术，将来或许甚至能在太空中建造一个巨型虫洞。我并不是说一定可以做到，但如果真的有这种装置，那么确实很了不起。一端在地球的附近，另一端则在遥远的星球附近。从理论上讲，虫洞或时光隧道不仅仅能把我们带到别的星球。一端在地球的附近，另一端则在遥远的星球附近。
10 Theoretically, a time tunnel or wormhole could do even more than take us to other planets. If both ends were in the same place, and separated by time instead of distance, a ship could fly in and come out still near Earth, but in the distant past. Maybe dinosaurs would witness the ship coming in for a landing.
从理论上讲，虫洞或时光隧道不仅仅能把我们带到别的星球。如果两端在同一个地方，且由时间而非距离分离，在遥远的过去，飞船就能在地球附近自由出入。或许恐龙会看到飞船登陆的场景。
11 The fastest manned vehicle in history was Apollo 10. It reached 25,000mph. But to travel in time we'll have to go more than 2,000 times faster .
在人类历史上，速度最快的载人飞船“阿波罗”10号，速度为每小时2.5万英里(约合每小时4万公里)，但要实现在时间中旅行，我们的速度必须是“阿波罗”10号速度的2000倍。
12 Now, I realise that thinking in four dimensions is not easy, and that wormholes are a tricky concept to wrap your head around, but hang in there.
如今，我意识到以四维方式思考并不容易，虫洞是一个令你绞尽脑汁的概念。
13 A well-known problem with time travel to the past, the problem of what we call paradoxes. Paradoxes are fun to think about. The most famous one is usually called the Grandfather paradox. I have a new, simpler version I call the Mad Scientist paradox.
一个原因可能是回到过去的时间旅行所存在的问题——我们称之为悖论，一个众所周知的问题。探讨悖论是一件很有趣的事情，最著名的悖论通常被称为“祖父悖论”。我有一个新的简化版本——“疯狂科学家”悖论。
14 I don't like the way scientists in movies are often described as mad, but in this case, it's true. This chap is determined to create a paradox, even if it costs him his life. Imagine, somehow, he's built a wormhole, a time tunnel that stretches just one minute into the past.
我不喜欢一些电影中科学家被描述成疯狂的群体，但在这种情况下，确实如此。这个家伙决心建立一个悖论，即便付出生命代价在所不惜。可以想见，他是在建造虫洞——仅需一分钟就来到过去的时光隧道。通过虫洞，这位科学家可以看到
他一分钟以前的自我。
15 Through the wormhole, the scientist can see himself as he was one minute ago. But what if our scientist uses the wormhole to shoot his earlier self? He's now dead. So who fired the shot? It's a paradox. It just doesn't make sense. It's the sort of situation that gives cosmologists nightmares.
如果这位科学家利用虫洞向以前的自我开枪，会发生什么事情？他现在已经一命呜呼。那又是谁开的枪呢？这便是一个悖论，听上去毫无意义。但这却是那种让宇宙学家做噩梦的状况。
16 This kind of time machine would violate a fundamental rule that governs the entire universe - that causes happen before effects, and never the other way around. I believe things can't make themselves impossible. If they could then there'd be nothing to stop the whole universe from descending into chaos. So I think something will always happen that prevents the paradox. Somehow there must be a reason why our scientist will never find himself in a situation where he could shoot himself. And in this case, I'm sorry to say, the wormhole itself is the problem.
这种时间机器会违反整个宇宙所遵循的基本规则。我认为一切皆有可能。如果真是如此，那么就没有任何办法阻止整个宇宙陷入混乱。所以，我认为有些事情总会发生以阻止这种悖论。在某种程度上，这或许是科学家永远不会发现他面临向自己开枪境地的原因。在这种情况下，我只能遗憾地告诉大家，虫洞本身就是一个问题。
17 In the end, I think a wormhole like this one can't exist. And the reason for that is feedback. If you've ever been to a rock gig, you'll probably recognise this screeching noise. It's feedback. What causes it is simple. Sound enters the microphone. It's transmitted along the wires, made louder by the amplifier, and comes out at the speakers. But if too much of the sound from the speakers goes back into the mic it goes around and around in a loop getting louder each time. If no one stops it, feedback can destroy the sound system.
最后，我认为像这样的虫洞不能存在，原因就是反馈。如果你有到摇滚演唱会现场观看演出的经历，你可能会辨别出这种尖利的噪音。这就是反馈，引起反馈的原因很简单。声音进入麦克风，通过电线传播，经由扩音器令声音放大，在一个环状物内绕来绕去，每次令声音比上一次更大。如果没人阻止，反馈能够破坏音响系统。
18 The same thing will happen with a wormhole, only with radiation instead of sound. As soon as the wormhole expands, natural radiation will enter it, and end up in a loop. The feedback will become so strong it destroys the wormhole. So although tiny wormholes do exist, and it may be possible to inflate one some day, it won't last long enough to be of use as a time machine.
虫洞也会遇到这种问题，只不过声音换成了辐射。一旦虫洞变大，大自然的辐射物会进入，最终形成一个环路。反馈变得如此强劲，最终摧毁虫洞。虽然微型虫洞确实存在，也有可能在某一天不断膨胀，但持续时间不会太长久，所以不能当
作时间机器使用。
19 Any kind of time travel to the past through wormholes or any other method is probably impossible, otherwise paradoxes would occur. So sadly, it looks like time travel to the past is never going to happen. A disappointment for dinosaur hunters and a relief for historians. 任何通过虫洞和其他方式回到过去的时间旅行或许都是不可能的，否则，悖论就会出现.因此，遗憾的是，回到过去的时间旅行应该永远不会上演。对于寻找恐龙的人来说，这会令他们大失所望，但对于历史学家而言，他们可以彻底解脱了。
Text1 Habits are a funny thing. We reach for them mindlessly, setting our brains on auto-pilot and relaxing into the unconscious comfort of familiar routine. “Not ch In but habit rules the unreflecting herd,” William Wordsworth said in the 19th century. the ever-changing 21st century, even the word “habit” carries a negative connotation. So it seems antithetical to talk about habits in the same context as creativity and innovation. 习惯是件有趣的事情。我们无意识间养成了一些习惯，我们的大脑是自动运 转的，轻松进入熟知套路所带来的不自觉舒适状态。“这并非选择，而是习惯控 制了那些没有思想的人”，这是威廉?华兹华斯（William Wordsworth）19世纪时 说的话。在现在这个日新月异的21世纪，甚至习惯这个词本身也带有负面涵义。 因此，在创造和革新的背景下来谈论习惯，似乎显得有点矛盾。 But brain researchers have discovered that when we consciously develop new habits, we create parallel synaptic paths, and even entirely new brain cells, that can jump our trains of thought onto new, innovative tracks. But don’t bother trying to kil off old habits; once those ruts of procedure are worn into the hippocampus, they there to stay. Instead, the new habits we deliberately ingrain into ourselves create parallel pathways that can bypass those old roads. 但大脑研究人员发现，当我们有意识地培养新的习惯的时候，我们创建了平 行路径，甚至是全新的脑细胞，可以让我们的思路跳转到新的创新轨道上来。但 是，不必费心试图摈弃各种旧习惯；一旦这些程序惯例融进大脑，它们就会留在 那里。相反，我们刻意培养的新习惯会创建平行路径能避开原来那些老路。 “The first thing needed for innovation is a fascination with wonder,” says D Markova, author of “The Open Mind” and an executive change consultant for Professional Thinking Partners. “But we are taught instead to ‘decide,’ just as decide is to kill off president calls himself ‘the Decider.’” She adds, however, that “to all possibilities but one. A good innovational thinker is always exploring the many other possibilities.” 大学英语
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
human creations, language may be the most remarkable. Through language we share experience, values, exchange ideas, transmit knowledge, and sustain culture. Indeed, language is vital to sense of reality by giving meaning to events. 在人类所有的创造中，语言也许是影响最为深远的。我们用语言来分享经验，表达(传递？)价值观，交换想法，传播知识，传承文化。事实上，对语言本身的思考也是至关重要的。和通常所认为的不同的是，语言并不只是简单地反映现实，语言在具体描述事件的时候也在帮助我们建立对现实的感知。——语序的调整。 Good speakers have respect for language and know how it works. Words are the tools of a speaker?s craft. They have special uses, just like the tools of any other profession. As a speaker, you should be aware of the meaning of words and know how to use language accurately, clearly,vividly,and appropriately. 好的演讲者对语言很重视，也知道如何让它发挥更好的效果。词语是演讲者演讲的重要“武器”，具有特殊的用途，这和任何其他的工作技艺没什么两样。作为演讲者，必须知道词语的具体含义，也要懂得如何做到用词准确、清晰、生动、适当。 Using language accurately is as vital to a speaker as using numbers accurately to a accountant. Never use a word unless you are sure of its meaning. If you are not sure, look up the word in the dictionary. As you prepare your speeches, ask yourself constantly, “What do I really want to say? What do I really mean?” Choose words that are precise and accurate. 演讲者准确地使用语言和会计准确使用数字是一样重要的。确定词意后再措词。如果不确定，请先查词典。当你在准备演讲的时候，要不断地问自己：“我到底要说什么？我到底想表达什么意思？”用词一定要精准。 Using language clearly allows listeners to grasp your meaning immediately. You can ensure this [by using familiar words （that are known to the average person and require no specialized background）; by choosing concrete words in preference to more abstract ones, and by eliminating verbal clutter]. 用词清晰可以让听众迅速理解你的意思（抓到你的点）。要做到这一点，就要尽量使用一般人都熟悉的不需要专业知识就能懂的词语；多用具象词汇少用抽象词汇；还有要减少口误。 Using language vividly helps bring your speech to life. One way (to make your speech vivid)|is through imagery，or the creation of word pictures. You can develop imagery by using concrete language, simile, and metaphor. Simile is an explicit comparison between things （that are essentially different yet have something in common）; it always contains the words “like”or “as”. Metaphor is an impli cit comparison between things that are different yet have something in common; it does not contain the words “like” or “as”. 生动地用词能让演讲鲜活起来！比喻，这种能产生文字图像的修辞，可以使演讲达到生动的效果。比喻要用具象的语言，分为明喻和隐喻。 明喻是指在本质上有区别但仍然有相同点的事物之间做一个明确的比较，一般句中会含有“像”或“似”。隐喻则是一种隐藏的比较，不会出现like 和as 这些连接词。 Another way to make your speeches vivid is by exploiting the rhythm of language. Four devices for creating rhythm are parallelism, repetition, alliteration, and antithesis. Parallelism is the similar arrangement of a pair or series of related words, phrases, or sentences. Repetition is the use of the same word or set of words at the beginning or end of successive clauses or sentences. Alliteration comes from repeating the initial constant sounds of close or adjoining words. Antithesis is the juxtaposition of
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
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。
Presenting a speech （做演讲） Of all human creations, language may be the most remarkable. Through 在人类所有的创造中，语言也许是影响最为深远的。我们用语言 language we share experience, formulate values, exchange ideas, transmit 来分享经验，表达(传递？)价值观，交换想法，传播知识， knowledge, and sustain culture. Indeed, language is vital to think itself. 传承文化。事实上，对语言本身的思考也是至关重要的。[Contrary to popular belief], language | does not simply mirror reality but also helps to create our sense of reality [by giving meaning to events]. 和通常所认为的不同的是，语言并不只是简单地反映现实，语言在 具体描述事件的时候也在帮助我们建立对现实的感知。 ——语序的调整。 Good speakers have respect for language and know how it works. Words are the tools of a speaker’s craft. They have special uses, just like the tools of any other profession. As a speaker, you should be aware of the meaning of words and know how to use language accurately, clearly,vividly,and appropriately. 好的演讲者对语言很重视，也知道如何让它发挥更好的效果。词语是演讲者演讲的重要“武器”，具有特殊的用途，这和任何其他的工作技艺没什么两样。作为演讲者，必须知道词语的具体含义，也要懂得如何做到用词准确、清晰、生动、适当。 Using language accurately is as vital to a speaker as using numbers accurately to a accountant. Never use a word unless you are sure of its meaning. If you are not sure, look up the word in the dictionary. As you prepare your speeches, ask yourself constantly, “What do I really want to say? What do I really mean?”Choose words that are precise and accurate. 演讲者准确地使用语言和会计准确使用数字是一样重要的。确定词意后再措词。如果不确定，请先查词典。当你在准备演讲的时候，要不断地问自己：“我到底要说什么？我到底想表达什么意思？”用词一定要精准。 Using language clearly allows listeners to grasp your meaning immediately. You can ensure this [by using familiar words （that are known to the average person and require no specialized background）; by choosing concrete words in preference to more abstract ones, and by eliminating verbal clutter]. 用词清晰可以让听众迅速理解你的意思（抓到你的点）。要做到这一点，就要尽量使用一般人都熟悉的不需要专业知识就能懂的词语；多用具象词汇少用抽象词汇；还有要减少口误。 Using language vividly helps bring your speech to life. One way (to make your speech vivid)|is through imagery，or the creation of word pictures. You can develop imagery by using concrete language, simile, and metaphor. Simile is an explicit comparison between things （that are essentially different yet have something in common）; it always contains the words “like”or “as”. Metaphor is an implicit
Lesson 8 IV. Translation Put the following into Chinese. 1. Every war has had its songs that whipped up patriotic fervor or, in the case of the Vietnam War that encouraged protest against it. 每场战争都有自己的歌曲来唤起人们的爱国热情或者如在越南战争中鼓励人们反战。 2. The idea is to take a song that people like or that has particular meaning or emotional association for them and use it with new words, hoping that some of the liking, meaning, or emotional associations will transfer to the new ideas being communicated. And it often works. 改词是把一首人们喜爱或者对他们具有特殊意义或感情色彩的歌曲填上新词，希望把这种喜爱、意义或感情色彩带到正在传播的新观念中。通常这种方法很奏效。 3 As a result, a number of community and national groups have applied pressure on stations to keep these songs and performers off the air. These charges also stimulated investigations by the Federal Communications Commission, the regulatory agency charged with overseeing broadcast practices. 结果一些社团和全国性团体向电台或电视台施加压力让他们禁播这些演员的节目。这些指控也促使负责广播业的监管机构联邦通讯委员会开始进行调查。 4. Does it mean a station should permit no language or ideas in a song that it would not permit on the news or in a sports program? Or does it mean the station should recognize that different forms of communication or entertainment, or programs designed for different kinds of audiences, should have different standards concerning language and ideas? 这是否意味着在广播电台或电视台播放的歌曲中不允许出现那些在新闻或体育节目中禁止出现的语言和观念？或者这是否意味着电台或电视台应该承认不同的交流或娱乐形式，或是为不同听众设计的节目，在语言和观念上应该具有不同的标准？ 5. One author has suggested that popular music also serves a "rite of passage" function for young girls. The teenage singing idols may serve as non-threatening substitutes for actual boys until boys' maturation catches up with that of girls and some semblance of easy boy-girl relationships can be established. 一位作者指出流行音乐也成了女孩子们成熟的标志。在同龄男孩子成长为像女孩子那样成熟并能较容易地与女孩子建立朋友关系之前，少年歌星可能会成为不会对女孩子形成威胁的男友的替身。 V. Oral Practice and Discussion 1. How was music used during World War II and during the Vietnam War? 2. Describe peacetime uses of music. 3. List the major effects and functions of music. 4. Identify the basic issues in the FCC regulatory position. 5. What problems do you foresee in the development of record labeling plans? 6. Adaptation of popular or favorite songs is a persuasive tactic. Where is this technique used today? Cite several examples. (Hint: Advertising commercials) 7. If music shapes our perceptions and attitudes, then, should we be forced to listen to music in public places such as restaurants and shopping malls? 8. Are there other effects of music not included in this article?
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