1、状语从句状语从句指句子用作状语时，起副词作用的句子。它可以修饰谓语、非谓语动词、定语、状语或整个句子。根据其作用可分为时间、地点、原因、条件、目的、结果、让步、方式和比较等从句。状语从句一般由连词(从属连词)引导，也可以由词组引起。从句位于句首或句中时通常用逗号与主句隔开，位于句尾时可以不用逗号隔开。1. 时间状语从句(1)时间状语从句常用when, as（当.时候）, while, before, after, since, till, until, as soon as等连词来引导。例如：He had learned a little Chinese before he came to C
2、hina.After he finished middle school, he went to work in a factory.(2)在时间状语从句里，主句用将来时态时，从句通常不用将来时态，用现在时态表示将来的动作或状态。（主将从现）例如：Ill ring you up as soon as I get to New York.I will tell him everything when he comes back.He wont believe it until he sees it with his own eyes.(3)在带有till或until引导的时间状语从句的主从复合句
3、里，如果主句用肯定式，其含义是“一直到时”，谓语动词只能用延续性动词。如果主句用否定式，其含义是“直到才”,“在以前不”, 谓语动词可用瞬间性动词。例如：The young man read till the light went out.Lets wait until the rain stops.We wont start until Bob comes.Dont get off until the bus stops.2. 条件状语从句(1)条件状语从句通常由if, unless(除非)引导。例如：What shall we do if it snows tomorrow?Dont le
4、ave the building unless I tell you to.(2)在条件状语从句里，谓语动词通常用现在时态表示将来的动作或状态。（主将从现）例如：（必考）Ill help you with your English if I am free tomorrow.He wont be late unless he is ill.(3)“祈使句 + and (or)+ 陈述句” 在意思上相当于一个带有条件状语从句的复合句。例如：Hurry up, or youll be late.=If you dont hurry up, youll be late.Study hard and
5、you will pass the exam.=If you study hard, you will pass the exam.3. 原因状语从句(1)原因状语从句通常由because, since, as引导。例如：He didnt come to school because he was ill.As it is raining, we shall not go the zoo.Since you cant answer the question, Ill ask someone else.(2)because表示直接原因，语气最强。Because引导的原因状语从句多放在主句之后。A
6、s和since语气较弱，一般用来表示明显的原因。由as和since引导的原因状语从居多放在句首。例如：-Why arent going there?-Because I dont want to.As he has no car, he cant get there easily.Since we have no money, we cant buy it.(3)because和so不能同用在一个句子里。4. 结果状语从句(1)结果状语从句由sothat, suchthat引导。例如：He is so poor that he cant buy a bike for his son.She i
7、s such a good teacher that everybody likes her.(2)sothat与such.that可以互换（可能会考）。例如：在由so.that引导的结果状语从句中，so是副词，与形容词连用。其结构是: “.so + 形容词（副词）+ that + 从句”。例如：Mother lives so far away that we hardly ever see her.在由suchthat引导的结果状语从句中，such是形容词，它修饰的可以是单数或复数可数名词，也可以是不可数名词；名词前面可以带形容词，也可不带。如果是单数可数名词，前面需加不定冠词a或an。例如
8、：It was such a hot day that nobody wanted to do anything.有时上述两种结构是可以互换的。例如：It was such a wonderful film that all of us wanted to see it again.=The film was so wonderful that all of us wanted to see it again.It is such an important match that nobody wants to miss it.=The match is so important that no
9、body wants to miss it.(3)如果名词前由many, much, little, few等词修饰时，只能用so, 不用such。例如：Soon there were so many deer that they ate up all the wild roses.He has so little time that he cant go to the cinema with you.5. 比较状语从句比较状语从句通常由asas（否定not so/as.as）, 比较级 + than等连词引导。例如：Tom runs faster than John does.This cl
10、assroom is as big as that one.6. 目的状语从句(1)目的状语从句通常由 so that, in order that引导。例如：We started early so that we could catch the first train.He studies hard so that he could work better in the future.We used the computer in order that we might save time.(2)so that既可引导目的状语从句，又可引导结果状语从句。区别这两种从句的办法有两个：1)目的状
11、语从句里往往带有情态动词can, could, may, might等。2)从意思上看，目的状语从句往往表示的目的很明确。例如：Speak clearly so that they may understand you. (目的状语从句)Jack is badly ill so that he has to rest. (结果状语从句)7. 让步状语从句(1)让步状语从句通常由although, though等连词引导。例如：Though he is young, he knows a lot.Although I am tired, I must go on working.(2)altho
12、ugh(though)与but不能用在同一个句子中。例如：我们不能说：Though it was raining hard, but he still went out.应该说：Though it was raining hard, he still went out.或It was raining hard, but he still went out.8. 地点状语从句地点状语从句常常由where来引导。例如：Go where you like.Where there is a will, there is a way.易混引导词while, when的区别：1.when既可以指时间点,与
13、瞬间动词连用，也可以指时间段，与延续性动词连用（=while）。如：When he came in, his mother was cooking.When (While) we were at school, we went to the library every day.While表示时间段,因此，while 从句的谓语动词要用延续性动词。如：Please dont talk so loud while others are working.2Because,as,since 的区别：Because用于表示直接原因,回答why提出的问题，语气最强；As用于说明原因, 着重点在主句，常译成
14、由于；since表示显然的或已知的理由或事实，常译成既然。如：Water is very important because we cant live without it.He didnt come yesterday as his mother was ill.Ill do it for you since you are busy.【实例解析】1.You will stay healthy _ you do more exercise, such as running and walking.A. if B. how C. before D. where2. -Shall we go o
15、n working?-Yes, _ I prefer to have a rest.A. when B. if C. because D. though3.None of us knew what had happened _ they told us about it.A. when B. until C. after D. though4.-I hope youll enjoy your trip, dear!-Thank you, mum. Ill give you a call _ I get there.A. until B. as soon as C. since D. till考
16、点精炼一. 单项填空1. _ hes old, he can still carry this heavy bag.A. Though B. Since C. For D. So2. -Do you know if he _ to play basket ball with us?-I think he will come if he _ free tomorrow.A. comes; is B. comes; will be C. will come; is D. will come; will be3. In the zoo if a child _ into the water and
17、cant swim, the dolphins may come up _ him.A. will fall; to help B. falls; to helpC. will fall; help D. falls; helping4. I dont remember _ he worked in that city when he was young.A. what B. which C. where D. who5. We will stay at home if my aunt _ to visit us tomorrow.A. comes B. come C. will come D
18、. is coming6. The police asked the children _ cross the street _ the traffic lights turned green.A. not; before B. dont; when C. not to; until D. not; after7. I was late for class yesterday _ there was something wrong with my bike.A. when B. that C. until D. because8. Ill go swimming with you if I _
19、 free tomorrow.A. will be B. shall be C. am D. was9. In the exam, the _ you are, _ the _ mistakes you will make.A. careful; little B. more careful; fewestC. more careful; fewer D. more careful; less10. You should finish your lessons _ you go out to paly.A. before B. after C. when D. while11. I hurri
20、ed _ I wouldnt be late for class.A. since B. so that C. as if D. unless12. When you read the book, youd better make a mark _ you have any questions.A. which B. that C. where D. though13. The teacher raised his voice _ all the students could hear him.A. for B. so that C. because D. in order14. He too
21、k off his coat _ he felt hot.A. because B. as C. if D. since15. It is _ that wed like to go out for a walk.A. a lovely day B. too lovely a dayC. so lovely a day D. such lovely a day16. Mary had _ much work to do that she stayed at her office all day.A. such B. so C. too D. very17. _ I felt very tire
22、d, I tried to finish the work.A. Although B. Because C. As D. As if18. _ the day went on, the weather got worse.A. With B. Since C. While D. As19. _ well you can drive, you must drive carefully.A. So long as B. In order thatC. No matter how D. The moment20. Write to me as soon as you _ to Beijing.A.
23、 will get B. get C. getting D. got真题演练(2010河北省卷42. 1) Peter likes reading a newspaper_ he is having breakfast.A. until B. while C. because D. though(2010.江苏省盐城市12. 1)Many students didnt realize the importance of study_they left school.A.when B.until C.as D.after(2010四川省内江市39. 1)I dont know if it_tom
24、orrow.If it_,we wont go on a picnic.A.rains;rains B.will rain;rains C.will rain;will rain(2010山东省潍坊市29. 1)You have to leave now_you can catch the early bus.A.so that B.as soon as C.because D.if(2010浙江省衢州市23. 1) You should go over your test paper _ you hand it in .A. before B. though C. because D. as
25、 soon as(2010江苏省无锡市12. 1)Scientists say it may be a few years _it is possible to test the new medicine on patients.A.because B.after C.before D.since(2010年上海市37. 1)We will have no water to drink _we dont protect the earth.A.until B.before C.though D.if（2010江苏省扬州市41）-Could we play football in your pl
26、ayground,Sir?-No,_you have the principals permission（校长许可）.A.if B.unless C.because D.since（2010四川省成都市35. 1）I wont be able to understand what you say,_you speak too quickly.A.if B.though C.because（2010浙江省湖州市22，1）-Is everyone here today?-No.Tom is at home_he has got a bad cold.A.because B.if C.until D
27、.unless（2010山西省27，1）In summer , food goes bad easily _ it is put in the refrigerator.A. until B. if C. unless（2010河南省25，1）_its difficult to make her dream come true，she never gives upA.Though B.Unless C.Because D.If（2010山东省莱芜市27，1）-I hear Jack Chan will come to Laiwu next week.-Really? _ he comes, m
28、y younger sister will be very happy,AIf BUntil CUnless DBefore（2010贵州省铜仁市35，1）- May I go to the concert with you?- Im afraid not _ you have a ticket, because I have only one.A. since B. if C. unless D. though（2010山东省菏泽市27，1）Mary spends a lot of money on clothes _ her family is not rich.A. because B.
29、 though C. if D. so（2010黑龙江省鸡西市29，1）Usually, we dont know how important something is _ we lose it.A. or B. until C. as soon as（2010广西省定西市15，1）She had a stomachache_she ate something bad.A. so B. because C. or D. although(2010福建三明29. 1)Many children like fried chicken _it is unhealthy food.A.if B.bec
30、ause C.although（2010广西南宁32. 1）Mr.Brown knew nothing about the good news _his wife told it to him.A.before B.after C.since D.if（2010四川达州29. 1） I dont know if Jack_. If he_ , call me, please.A. will come; will comes B. comes; comeC. comes; will come D. will come; comes （2010天津市41，1）We wont start the m
31、eeting _our teacher arrives.A.though B.until C.while D.or（2010青海省宁夏33，1）-Did you catch what the teacher said?-No. She spoke so fast _ I couldnt hear her very clearly. A. which B. that C. when D. since（2010辽宁省沈阳市8，1） _ it snowed heavily yesterday, nobody in our class missed the lessonAThough BBecause
32、 CUnless DSince（2010江苏省镇江市8，1）A tourist will easily lose his way in Beijing _ he has a map or a guide.A. if B. because C. unless D. when（2010广东省18，1）The teacher speaks very loudly_all the students can hear her.A. so that B. because C. since D. whenKeys: 【练习答案】 1.A 2.C 3.B 4.C 5.A 6.C 7.D 8.C 9.C 10.A 11.B 12.C 13.B 14.A 15.C 16.B 17.A 18.D 19.C 20.B真题演练BBBAA CDBCA CAACB BBCAD BBACA
