语法讲解时间状语从句的用法解析及练习
状语从句在复合句中作状语，其位置较灵活，可以在主句之前、之后或中间(放在句首时状语从句后面常用逗号，放在句末时状语从句前面往往不用逗号)。根据状语从句的含义，状语从句主要分为时间状语从句、地点状语从句、原因状语从句、目的状语从句、方式状语从句、结果状语从句、条件状语从句、让步状语从句等八种。掌握以上各种状语从句的关键在于把握其相应的引导词。以下是对时间状语从句的基本用法进行小结，希望可以帮助到同学们有一更深的理解。
时间状语从句的引导词
when, before, after, as, while, till/until, since，whenever
时间状语从句的用法
时间状语从句的引导词所表示的意思不尽相同，要注意把握不同的时间状语从句的引导词所表示的不同时间关系，以及它在具体句子中对应的对应时态、语态等问题。
1. when、as、while引导的时间状语从句分析：
(1) when引导时间状语从句时表示“当……的时候”，when既可以指时间段也可指时间点，从句中既可用延续性动词又可用非延续性动词，且动作既可和主句的动作同时发生又可在主句的动作之前或之后发生。
注意体会如下例句：I’ll call you when I get there. 我一到那里就给你打电话。// When the wind blows, all the doors rattle. 只要风一吹，这门就吱嘎作响。// He stopped trying, when he might have succeeded next time. 他不再试了，其实他可能下一次就成功。// When I came home my wife was cooking dinner. 我回家时，妻子在做晚饭。
如果when引导的时间状语从句的主语与主句主语相同，而从句的谓语又是be动词时，那么从句中的主语和be可以省略;当when引导的时间状语从句的主语与主句主语相同时，往往还可以用“when+分词”的形式替代该状语从句。例如：When (you are) in trouble, ask her for help. 当你遭遇麻烦的时候去向她求助。// When I came into the room (=When coming into the room), I found him lying there asleep. 当我进入房间的时候，我发现他躺在那儿睡着了。
(2) while引导时间状语从句时表示“当……的时候”，它强调主句的动作与从句的动作同时持续地进行，用于这一用法时while引导的时间状语从句和主句中的谓语动词必须是延续性动词，或者主句的动作发生在从句动作的进行过程中，主句中的谓语动词通常是非延续性动词，例如：Study while you study; play while you play. 该学习的时候就学习，该玩的时候就玩。// I met her while I was at school. 当我在学校的时候我遇见了她。
(3) as引导时间状语从句时表示“当……时，一边……一边……”，侧重表示两个动作同时发生(包括一个主语同时进行两个动作)，或者一种动作随着另一种动作的变化而变化。例如：He jumps as he goes along. 他边走边跳。// I slipped on the ice as I ran home. 我跑回家时在冰上滑了一跤。// I saw him as he was getting off the bus. 正当他下公共汽车时, 我看见了他。// As the wind rose the noise increased. 刮风的时候噪声增大。
[考题1] I had just steeped out of the bathroom and was busily drying myself with a towel ____ I heard the steps.
A. while
B. when
C. since
D. after
[答案] B
[解析] 下划线处表示“正在这时，突然……”，四个选项中只有when可以表示此含义。
[考题2] He was about halfway through his meal ____ a familiar voice came to his ears.
A. why
B. where
C. when
D. while
[答案] C
[解析] 下划线处表示“正在这时，突然……”，四个选项中只有when可以表示此含义。
[考题3] We were swimming in the lake ____ suddenly the storm started.
A. when
B. while
C. until
D. before
[答案] A
[解析] 题意为“当我们正在湖里游泳的时候突然暴风雨开始了”，表示主句的动作处于从句的动作突然发生时应采用when(while不适合用于这样的语境)，when表示“当……的时候”受限制条件最少。
[考题4] —I’m going to the post office.
—____ you’re there, can you get me some stamps?
A. As
B. While
C. Because
D. If
[答案] B
[解析] 主句中“get me some stamps”的动作发生在时间状语从句“you’re there”的过程之中，因此应选while表示这一时间关系(属于while引导时间状语从句的两大基本用法之一)。因此B选项是最佳选项。
注意：如果主句的动作发生于表示“;当……时”的时间状语从句中的动作的进行过程中，从句常用进行时。例如：The landlady suspected that someone must have broken into the house when/while/as she was watching TV show. 女房东怀疑在她看电视时曾有人闯入屋里。// When/While/As Tom was reading, Jim was arrested. 在汤姆看书的时候，吉姆被逮捕了。
[考题5] I ____ along the street looking for a place to park when the accident ____.
A. went; was occurring
B. went; occurred
C. was going; occurred
D. was going; had occurred
[答案] C
[解析] 根据题干句子含义，事故发生于当我沿街行驶、寻找停车之处的时候;从句的动作发生在主句动作的过程中。主句的谓语动词go表示非延续性的动作，可以持续进行，应选用过去进行时的形式，从句的谓语动词为非延续性动词，应以一般过去时的形式表结果。
2. before和after 引导的时间状语从句分析：
before引导时间状语从句时表示主句的动作发生在从句动作之前，after引导时间状语从句时表示主句的动作发生在从句动作之后。例如：See me before you leave. 在你离开之前来见我。// Before they drive any of the buses, they will have to pass a special test. 在驾
驶公共汽车之前，他们必须通过专门测验。// I saw them after I arrived. 在我抵达之后，我见到了他们。// I found his pen after he has left. 在他走后，我找到了他的笔。
[考题6] He was told that it would be at least three more months ____ he could recover and return to work.
A. when
B. before
C. since
D. that
[答案] B
[解析] 表示“他康复并返回工作岗位之前至少还需要三个月”，下划线处应选用before。
[考题7] It was some time ____ we realized the truth.
A. when
B. until
C. since
D. before
[答案] D
[解析] 题干意为：过了一段时间我们才意识到真相。下划线处应填入表示“在……之前”的连词。
3. till和until 引导的时间状语从句分析：
till和until这两个词作连词和介词时的意义和用法相同，一般可以换用(放在句首时通常用until的形式，till在口语中更为常见)。till和until引导时间状语从句时跟主句里肯定形式或否定形式的、表示延续性动作的谓语动词连用表示“到……为止”，跟主句里否定形式的、表示非延续性动作的谓语动词连用表示“直到……才(开始)”，例如：Walk till you come to a white house. 一直走到一座白房子为止。// We didn’t discuss the problem un til he came back. 我们一直等到他回来后才讨论问题。
[考题8] It is difficult for us to learn a lesson in life ____ we’ve actually had that lesson.
A. until
B. after
C. since
D. when
[答案] A
[解析] 题干的句子可以直译为：“在我们一生中，学到某个教训是困难的，直到我们真正经历了这个教训为止。”
[考题9] A good storytell er must be able to hold his listeners’ curiosity ____ he reaches the end of the story.
A. when
B. unless
C. after
D. until
[答案] D
[解析] 讲故事的人应该始终抓住听众的好奇心，本题应选用表示“到……为止”(跟主句里肯定形式的表延续性动作的谓语动词连用)的until 表示这一时间关系。
[考题10] I don’t really work here; I ____ until the new secretary arrives.
A. just help out
B. have just helped out
C. am just helping out
D. will just help out
[答案] C
[解析] “I don’t really work here”表明说话人只是临时前来帮忙，“until the new secretary arrives”表明说话人，工作到新秘书就任为止，本题应选用表示“到……为止”(跟主句里肯定形式的表延续性动作的谓语动词连用)的until表示这一时间关系。
4. since引导的时间状语从句分析：
since引导的时间状语从句表示“自从……以来”，其用法主要有两种：
(1) 现在完成时的主句+since引导的一般过去时态的时间状语从句。例如：He hasn’t been home since he graduated. 他毕业后没回过家。// They have been friends ever since they were in grade school. 他们从小学起就一直是好朋友。// What have you been doing since I last saw you? 自我上次和你见面以后，你在做什么?
(2) It be(主句中谓语用一般式和用完成式区别不大，后者更具强调意味)+表示一段时间的词汇+since引导的时间状语从句。例如：It is two years since I became a postgraduate student. 我成为研究生已经有2年了。It was three years since we had been there. 我们在那儿已呆了三年。
注意：since做介词时也表示“自从……以来”，其具体用法有两种情况：
(1) since+表示过去某个时间点的词汇(如具体的年、月、日期、钟点)。
例如：They have been friends since childhood. 他们从幼时起一直是好朋友。She’s been skiing since childhood. 她从幼时起就开始滑雪。I have been there many times since the war. 自那次战争以来，我曾去该地多次。
(2) since+表示一段时间的词汇+ago。
例如：I have been here since five months ago. 五个月以来我一直在这里。
[考题11] They ____ friends since they met in Shanghai.
A. have made
B. have become
C. have been
D. have turned
[答案] C
[解析] 题干中的since表示“自从……以来”，主句中的谓语动词应该表示从他们在上海相遇至今的持续性的动作，因此下划线处应填入可以表示持续性状态的have been(其他选项中的made、become、turned所表示的动作都不能延续，意味着结果)。
[考题12] — What was the party like?
—Wonderful. It’s been 2 years ____ I enjoyed myself so much.
A. after
B. before
C. when
D. since
[答案] D
[解析] since表示“自从……以来”。
一、选择题 1．I’ll go to visit my aunt in England the summer holidays start. A．as soon as B．since C．unless 2．—the water was cold , Wei Qinggang jumped into it to save others. A．Although B．When C．If D．Because 3．We always don't realize time goes by, ________we're playing games. A．while B．although C．unless D．if 4．You will never get anywhere you set a goal. So whatever we do, we should first have a goal. A．unless B．because C．though 5．___________ many people may surf the Internet for the latest news, it is impossible that the newspaper will disappear. A．Beacause B．Though C．Since D．Unless 6．Li Lei didn’t go to bed his mother came back last night. A．after B．until C．because 7．I don’t like nuts ________ they are too hard. A．if B．after C．when D．because 8．________decision you make, you must be prepared for the worst. A．Whoever B．Wherever C．Whenever D．Whatever 9．—If it________tomorrow, I’ll go fishing. — May I go along with you? A．didn’t rain B．won’t rain C．doesn’t rain 10．--We should go to school by bus instead of by car. --Yeah, cars we use, pollution there will be. A．fewer; less B．less; fewer C．the less; the fewer D．the fewer; the less 11．Mr. White tells us the calls meeting will be cancelled if no agreement _________ tomorrow. A．is reached B．will be reached C．is going to be reached D．has been reached 12．—You look so sleepy. What’s the matter with you , Carmen? —I’ve been working for ten hours. I am__________tired ___________ I want to sleep. A．so ; that B．such; that C．between; and D．neither; nor 13．_______you can sleep well, you will lose the ability to concentrate, plan and stay active after one or two nights. A．Once B．Unless C．If D．When 14．—My son hardly even eats vegetables________ it’s good for his h ealth. — Not a good habit.
中考语法专题条件状语从句（讲解+练习，无答案）
条件状语从句
常用引导词：if, unless, as/so long as
1、if 从句 + 祈使句，“如果……，就……”
If you do not feel well, please go to see the doctor. 如果你感觉不舒服，就去看医生 吧。
If you want to know more about it, call now. 如果你想了解更多内容，现在就打电话 吧。
Make sure you visit the Science Museum if you ever go to London. 如果你去伦敦，一 定要去参观科学博物馆。
2、主将从现
If I start after dinner, I’ll finish it before I go to bed. 如果我晚饭后开始，睡觉前我就能 完成。
主句也可用“情态动词 + 动词原形” She may come with us if she arrives in time. 如果她来得及时，就可以和我们一起去。
3、if 条件状语从句和并列句的转换
Hurry up, or you’ll be late. = If you don’t hurry up, you’ll be late. Study hard and you will pass the exam. = If you study hard, you will pass the exam. 练习 （一）句型转换 1. Run fast, or you’ll be late for school. _______ you _______ _______ fast, you’ll be late for school. 2. You can buy the dictionary if you take enough money with you. Take enough money with you, _______ _______ _______ buy the dictionary. 3. If there is no air, none of us can live. None of us can live _______ _______.
4、unless “除非”
Don’t leave the building unless I tell you to. 不要离开大楼，除非我准许。 Unless you have finished your homework, I won’t allow you to watch TV. 除非你已完成 了作业，否则我是不会让你看电视的。 unless = if not You’ll be late if you don’t hurry. = You’ll be late unless you hurry. I can’t catch the train if I don’t get up early. = I can’t catch the train unless I get up early.
练习
语法状语从句 由从句担任的状语,在句子中可修饰谓语(或其它动词)、形容词、副词或就是整个句子,它可以用来表示时间、地点、原因、目的、结果、条件、方式、比较、让步等。 第一讲时间, 地点状语从句 时间状语从句:when, while, as, before, after, since , whenever until, till, by the time(注意时态) as soon as, had hardly…when, had no sooner…than,(on doing sth…) the moment, every time/ each time, the first time, once e、g: When he came, I had cleaned the classroom、 He didn’t stop working until his mother came bake、 He worked until his mother came back、 As soon as he returned, he bought a new flat、 He had no sooner returned than he bought a new flat He came to scene the moment he heard the news、 I thought her nice and honest the first time I met him、 Once he makes up your mind, he won’t change his mind、 It was two years before I met him again、= Two years passed before I met him again、注意点1、when引导的从句动词可以就是延续性的或短暂性的,while引导的从句中动词必须就是延续性的; while有时并不表示时间,而表示对比,表示“而”、“却”。 When I got home I found the door locked、 While(或When)we were working in the fields, it suddenly began to rain、 His pencil is red, while mine is yellow、 2、till与until not…until/till 解释为直到…才…主句动词一般就是短暂性的 …till/until… 解释为直到…为止主句动词一般就是延续性的一般情况下可以互换,但until可以位于句首,till则不能。 He worked until it was dark、 He didn’t stop working until it was dark、 Until it stops raining,the children can’t go out、 ＝Not until the rain stops can the children go out、 地点状语从句 引导地点状语从句的连词就是where 与wherever等。 I ll go wherever the people want me to go、(wherever＝to any place where) He works where his grandfather fought、(where＝in the place where) You must stay where you are、= You must stay in the place where you are、 Wherever you go, I go too、 Where there is water, there is life、(那儿有… 那儿就有… Where there is a will, there is a way、) 圈出其中的从句并翻译: 1.Whenever it is his turn to speak, he gets nervous、 2.Every time he comes, he always tells us something interesting、 3.When I get the news, I will let you know as soon as possible、 4.Once he makes a promise, he will never break it、 5.I had no sooner run into the school gate than I heard the bell for class、 6.I found the lost watch under a desk after the children had left for home、 7.He had to be called two or three times before he came down to dinner、 8.We didn’t notice anything wrong with the washer until we started using it、 9.The hunter made mark on the tree where he stops、 10.Wherever he is, he will find time to do some reading、
1. Tim is in good shape physically ________ he does n't get much exercise. A. if B. even though C. uni ess D. as long as 2. The school rules state that no child shall be allowed out of the school duri ng the day, _____ accompa nied by an adult. A. once B. whe n C. if D. uni ess 3. ___ you may have, you should gather your courage to face the challenge. A. However a serious problem B. What a serious problem C. However serious a problem D. What serious a problem 4. Because of the heavy traffic , it was already time for lunch break ________ she got to her office . A . si nee B .that C . when D . until - 】Joh n thinks it won 't be long he is ready for his new job. A. whe n B. after C. before D. since 6. Today, we will begin we stopped yesterday so that no point will be left out. A. whe n B. where C. how D. what 7. She had just finished her homework her mother asked her to practice playing the piano yesterday. A. whe n B. while C. after D. since 8. My pare nts don ' t mind what job I do I am happy. A. even though B. as soon as C. as long as D. as though 9. You can ' t borrow books from the school library ______ you get your student card. A. before B. if C. while D. as 10. All the dishes in this menu, ______ otherwise stated, will serve two to three people. A. as B. if C. though D. unl ess 11. Because of the financial crisis, days are gone __ local 5-star hotels charged 6,000 yuan for one night. A. if B. whe n C. which D. since 12. ___ u nemployment and crime are high, it can be assumed that the latter is due to the former. 13. — Did you return Fred ' s call? 16. __________ in the fields on a March after noon , he could feel the warmth of spri ng. A . To walk B. Walking C. Walked D. Having walked 17. Na ncy enjoyed herself so much she visited her friends in Sydney last year. A.that B.which C.whe n D.where 18. You ' d better not leave the medici ne kids can get at it. A.eve n if B.which C.where D.so that 19. I won ' t call you , ________________ something unexpected happens. A.u nless B.whether C.because D.while 20. — Where' s that report? A. Before B. Where C. U nless D. Until —I didn ' t need to I ' ll see him tomorrow. A. though B. unl ess 14. _I ' m sorry you ' ve been waiting so long , Brian gets back. A. before B. since C. till C. whe n D. because but it ' ll still be some time _____ D. after 15. We ll have a picnic in the park this Sun day ____ ____ it rains or it ' s very cold. A.si nee B. if C. unl ess D. un til
条件句从句主句 真实一般现在时一般将来时 情态动词+动原祈使句 非真实 一般过去时 be动词用（were） would/could+动原初中英语――条件状语从句（讲解&练习） Ⅰ条件状语从句的定义 Ⅱ条件状语从句的引导词 1.if引导的条件状语从句：表示在某种条件下某事很可能发生。 If we pay much attention to the earth, we'll have a better world. 如果我们多关爱地球，就会拥有一个更美好的世界 If it rains tomorrow, what shall we do? 如果明天下雨，我们怎么办？ 注意：if还可以引导虚拟条件句，表示不可实现的条件，从句中多用一般过去时或过去完成时。 What would happen if there were no water ? 如果没有水会怎样？ 2.unless引导的条件状语从句，unless的意思是如果不，除非。可与if...not互换。 You will fail in English unless you work hard. 你英语考试会不及格的，除非你更加努力。 3.as /so long as引导的条件状语从句：as /so long as意思是“只要” So long as you're happy,i will be happy. 只要你高兴，我就高兴。 Ⅲ条件状语从句的种类 Ⅳ条件状语从句的时态原则 用法例句 ①主句为一般将来时态，if从句用一般 现在时态（即主将从现）。We will stay at home if it rains tomorrow. 如果明天下雨，我将要呆在家。 ②主句中含有情态动词，if从句用一 般现在时态。If you finish your homework, you can go home now.如果你做完了作业，你现在可以回家了。 ③主句为祈使句，if从句用一般现在 时态。Don’t jump into the river if you feel very hot. 如果你感到很热，不要跳入河里。 ④主句为过去将来时，if从句用一般 过去时态（如果涉及到be动词， 一律都用were）。此时，表达的是和现实相反的推测，用虚拟语 气。If I were you, I wouldn’t do it like that.如果我是你，我就不会那么做的。 If you gave me some money, I would be very happy. 如果你给我一些钱，我就会很高兴的。 二、if 引导的条件状语从句 （1）“if 从句+祈使句”的句子。其实，if 作为一个连词，主句也可以是其他形式的句子。 例如：If you want to go, please let me know. (2)“祈使句 + and (or)+ 陈述句”
从句 从句按其在主句中的句法功能可分为三类: 即名词性从句、形容词性从句(即定语从句)和副词性从句(即状语从句)。 引导从句的词称作关联句. 一、名词性从句 引导这些名词性从句的关联词包括: 从属连词that, if, whether; 连接代词 who,whoever,whom,whomever,which,whichever,what,whatever,wh ose; 连接副词where, when, why, how。 其中, 从属连词只起连接作用, 在从句中不充当任何句法成分, 而连接代词和连接副词既起连接作用, 在从句中又充当一定的成分. That Owen should have married his cousin is not at all surprising. The fact is that he didn't go to the dinner party. I don't know if he will attend the meeting. Have you heard the news that Mary is going to marry Tom? 你听说玛丽要和汤姆结婚的消息了吗?(that引导同位语从句) [提示]
1. 在含有主语从句的复合句中, 为保持句子平衡, 常用it作形式主语,而将真正的主语从句置于句末. It's well-known that water is indispensable to life.(形式主语) 2. 为保持句子平衡, that引导的宾语从句也常用it代替, 而将真正的宾语从句置于主句句末。这常常出现在主句有形容词或分词作宾语补足语的情况下。 He made it quite clear that he preferred to live here. 3. 从属连词whether和if都作“是否…”解, 但if不可引导主语从句和表语 从句。whether可与or(not)连用, 而if不可以。 I don't know whether (if) she is at home. Whether she comes or not makes no difference. 4. that和what引导名词性从句的区别: that在从句中不充当成分,而what在从句中充当一定的成分, 如主语、表语、宾语等。that可省略, what则不可省。 He always means what he says. She suggested (that) he do it at once. 5. 同位语从句大多由从属连词that引导, 常跟在下列名词后面, 如fact, idea, opinion, news, hope, belief等, that不可省。同位语从句一般用来解释说明这些名词的具体含义和内容。 We are familiar with the idea that all matter consists of atoms. The news that we are invited to the conference is very encouraging.
咼中英语状语从句 定义: 在句中作状语的从句是状语从句，修饰主句中的动词、形容词或副词等.状语从句由从属连词引导，从属连词在句中不充当句子成分，只起连接作用，状语从句放在句首时，要用逗号，放在句 尾时不用. 分类 根据意义上的不同，状语从句可分为：①时间状语从句②地点状语从句③原因状语从句④ 目的状语从句⑤条件状语从句⑥结果状语从句⑦让步状语从句⑧方式状语从句⑨比较 状语从句三、时间状语从句主句是一般将来时，时间状语从句用一般现在时表将来；主句是—过去将来时，从句用一般过去时表示过去将来时；主句是一般过去时忆：“主将 ，从句用一般过去时.记从现” (一)引导时间状语从句的连词有：As，whe n (whe never)，before，after，as soo n as，un til (till)，since，every time，once. | （二）、具体应用1）“while ”主、从句动作或状态同时发生.用while引导的从句用延续性 动词，常表示较长的时间或一个过程.记忆：While 后用进行时.While we were having supper， all the lights went out. Please kee p quiet while others are study in g」 While I was writing letters last night，he was watching TV. 2 ）When 表示“就在”的时候"， while 意为反而，可是，表示转折.One evening Beethoven was walking in a street，when he sudde niy stopped outside a little house. 3）When ever无论什么时候，随时 1.When ever some one throws in some rubbish，the truck p roduees a pi eee of music. 每当有人扔进一些垃圾时，它（汽车）就放一段音乐 2.When ever we' re in trouble，they will help us. 3.I go to the theatre, whe never I am free. https://www.doczj.com/doc/017126221.html,e and see me whe never you want to.你随时来看我 4) till和until(表示"直到” ”)句首多用until | 1在肯定句中表示“直到”为止”，主句谓语动词要用延续性动词 I was wait ing un til/till he arrived. 2、在否定句中表示“直到，，才”主句谓语动词常用终止性动词，这时until和till常被before 替换. I did n' t leave till/un til she came back. 5) si nee:主句用完成时，从句用一般过去时，si nee引导的从句间或可用现在完成时 It is two years since I have studied En glish. 1.We have known each other si nee we were childre n. 2.We have bee n friends （ever sin ce） since we met at school. 3.It is ”（一段时间）+since+—般过去时态句子 It is two years since my sister married. I
时间状语从句常由以下连接词引导：when（当……时），as（一边……一边；当…时），while（在……期间），after（在……之后），before（在……之前），as soon as（一……就），since（自从），till(until)（直到……，直到……才），whenever（任何时候），the moment（一……就），no sooner than（一……就），hardly…when… （一……就）等。由以上连接词（或词组）连接的主从复合句中，主句和从句的动作，有的是同时发生，有的是先后发生。因此，要特别注意根据连接词所代表的时间不同，主句和从句的谓语要使用相应的时态。这是掌握时间状语从句的关键。 1. when 和whenever 引导的从句：从句的动作和主句的动作可以同时发生，也可以先于主句的动作发生。例如： When we reached home, it was already dark. 我们到家的时候天已经黑了。 When my cousin came yesterday, I was playing volleyball. 昨天我表哥来时，我正在打排球。 When it rains, I go to school by bus.下雨的时候，我坐车去学校。 I shall tell her the good news when she comes. 她来时，我将告诉她这个好消息。（主从句都表示将来发生的动作，但要注意从句中要用一般现在时，表示将来。） Come to see us whenever you can.你什么时候有空，就过来看看我们。 2. while 和as 引导的从句：while表示“当…过程中”，强调某一段时间主句和从句的动作在同时发生。as表示“当…时”或 “一边…一边”，主句和从句的动作同时发生。例如： Work while you work; play while you play. 该工作的时候就工作，该玩的时候就玩。 While he is reading, he always makes notes. 他经常一面看书，一面做笔记。 She sings as she goes along.她边走边唱。 You will grow wiser as you grow older. 随着年龄的增长，你会更加聪明起来。 3. before 和after 引导的从句：前者一般表示主句的动作发生在从句动作之前。后者表示主句的动作发生在从句动作之后。 例如： I didn’t know any English before I came here. 我来这儿之前，一点英语都不懂。 I had written my report before my mother came back.
条件状语从句讲解 ――if引导的条件状语从句（注意&练习）在句子中做条件状语的从句称为条件状语从句。可置于句首、句尾，有时还可置于主语和谓语之间。引导条件状语从句的连接词有：if ,unless,as/so long as等 1.if引导的条件状语从句 表示在某种条件下某事很可能发生。 If we pay much attention to the earth, we'll have a better world. 如果我们多关爱地球，就会拥有一个更美好的世界 If it rains tomorrow, what shall we do? 如果明天下雨，我们怎么办？ 注意：if还可以引导虚拟条件句，表示不可实现的条件，从句中多用一般过去时或过去完成时。What would happen if there were no water ? 如果没有水会怎样？ 2.unless引导的条件状语从句 unless的意思是如果不，除非。可与if...not互换。 You will fail in English unless you work hard. 你英语考试会不及格的，除非你更加努力。 3.as /so long as引导的条件状语从句 as /so long as意思是“只要” So long as you're happy,i will be happy. 只要你高兴，我就高兴。 4.once引导的条件状语从句 once引导的条件状语从句，意为“一旦...，就”，从句可置于主句前或后 Once you begin,never stop. 一旦开始，就绝不要停止 Maths is easy to learn once you understand the rules. 一旦你理解了规则，数学就不难学了。
条件状语从句 概念定义 由引导词if或unless引导的状语从句叫做条件状语从句。在英文中，条件是指某一件事情实现之后（状语从句中的动作），其它事情（主句中的动作）才能发生，通常译作“假如”。（注意：在含有条件状语从句的复合句中，表示将来时态，主句是一般将来时态,祈使句或情态动词，从句要用现在时态,[主将从现原则]（主将从现，将并非指将来时，还指表示将来含义的，跟着if后的那句话是从句。） 类型 条件状语从句 语法引导条件状语从句最常用的连词是if,由if引导的条件状语从句表示在某种条件下某事很可能发生。如： 1） If you ask him,he will help you. 如果你请他帮忙，他会帮你的。 2） If you fail in the exam,you will let him down. 如果你考试不及格，你会让他失望的 if引导的条件状语从句既可以将从句放前面也可以将从句放后面 （如果天下雨，我们就不玩了）If it rains,we will stop playing.‘ 转为We will stop playing if it rains. if引导的条件状语从句
另外，if从句还表示不可实现的条件或根本不可能存在的条件，也就是一种虚拟的条件或假设，从句多用一般过去时或过去完成时。如：If I were you,I would invite him to the party.如果我是你，我会邀请他参加聚会。I would have arrived much earlier if I had not been caught in the traffic.如果没有堵车，我会到的早一点儿。 那么，除了if之外，是否还有其他连词也可以引导条件状语从句呢?回答是肯定的，不仅有，还有很多。这些词由于出现的频率较小，且用法较复杂一些，所以不如if为大家所熟知罢了。下面就这些词的用法以例句的形式进行一下简单总结。 1、unless conj.除非，若不，除非在……的时候 You will fail to arrive there in time unless you start earlier.如果你不早点动身，你就不能及时赶到那儿。 Unless it rains,the game will be played.除非下雨，比赛将照常进行。 2、on condition(that)...在……条件下，如果 on condition (that)...引导的条件从句是主句事件发生的前提条件或唯一条件。 I can tell you the truth on condition that you promise to keep a secret.我可以告诉你真相，条件是你答应保密。 You can go swimming on condition (that) you don't go too far from the river bank.你只有在不远离河岸的条件下才可以下水游泳。 3、supposing conj.如果，假如 supposing引导的条件从句表示一种假设条件。 Supposing it rains,shall we continue the sports meeting?倘若下雨，我们的运动会还要继续举行吗? Supposing anything should go wrong,what would you do then?假如出了什么问题，你准备怎么对付?
初中英语语法状语从句讲解专项练习选择合适的连接词，完成下列句子。 spends a lot of money on books______he is not rich. fell into sleep ______she was listening to the music. David at school today ----No. He is at home ______he has a bad cold. , won't have supper ______my mother comes back. to him slowly ______he may understand you better. 6. ______ she doesn't come on Sunday, I'll go fishing by myself. is four years ______I had left that small village. 8. ______the air moves, it is called wind. will go to the park ______it doesn't rain tomorrow. boys did ______much work. are few new words in the passage ______we can't understand it. ? back ______you come from. reached the station ______the train had left. you have a swimming pool ----No, we don't. At least, not ______big ______yours. me your paper ______you have finished it. is raining hard, ______we have to stay at home. 17. ______you work harder, you'll never pass the final exam. after the children ______I am out. ' village is ______far away ______I can't get there on foot. is ______an interesting book ______I can't stop reading it. 能力提高练习 1 ( ) 1 The meeting didn't start___ everyone was there. A. because B. until C. why D. if ( ) 2 The boy ___ to bed ___ his mother came in. A. went not; until B. didn't go; after C. went; until D. didn't go; until ( ) 3 I won't believe you___ I have seen it with my own eyes. A. before B. until C. after D. when ( ) 4 He ___ home ___ she was satisfied ___ his answer yesterday. A. didn't go; until; with B. wasn't go; after; to C. doesn't go; before; with D. didn't go; until; to ( ) 5 He ___ back until the work ___ done. A. isn't; will be B. isn't; is C. won't be; will be D. won't be; is ( ) 6 They didn't start the work ___ their teacher came back. A. until B. while C. as soon as D. if 2 ( ) 1 Tom will call me as soon as he ___ Shanghai. A. arrives B. will reach C. arrives in D. get to ( ) 2 I'm sure he'll come to see me before he ___ Beijing. A. will leave B. is leaving C. leave D. leaves ( ) 3 I will tell him the news as soon as he___ back. A. come B. comes C. will come D. came 3 ( ) 1 Tom has got a watch. He ___ it for two years. It _______ by his father. A. has bought; was bought B. has got; is bought , C. was bought; has bought . D. has had; was bought "' ( ) 2 When he got to the station, the train ___. A. left B. had left C. leaves D. has left
初中英语语法专题讲座——状语从句 状语从句在复合句中作状语，修饰动词、形容词或副词等。状语从句可以表示时间、条件、原因、地点、目的、结果、让步、方式、比较等意义。 知识梳理：提纲挈领，抓住重点和难点！ 各类状语从句连接词（短语）一览表： 时间 when, while, as, as soon as, since, until, after, before，as long as（长达……之久） 条件 If, unless,as/so long as(只要) 原因 As, because, since，as/so long as(既然,因为) 地点 Where 目的 So that(为了), in order that 结果 So that（方便）, so…that,such…that 让步 though, although, even if, however 方式 As 比较than, (not)as…as, 时间状语从句： Whenever he comes, he brings a friend. 他每次来都带个朋友。 They all continued their regard for me as long as they lived. 他们毕生都在关心着我. 条件状语从句： As long as I am alive, I will go on studying. 只要我活着，我就要学习。 原因状语从句： Since we live near the sea, we enjoy nice weather.由于我们住在海边，能享受到好的天气。 地点状语从句： Put it where we can all see it.把它放在我们都能看到的位置。 目的状语从句： Finish this so that you can start another.把这个做完，（为了）你可以开始另一个。 结果状语从句： He was so angry that he couldn't say a word. 他气得说不出话了。 让步状语从句： Though he is in poor health, he works hard.虽然他身体不好，但是他工作很努力。