whenifbeforeuntil從句

1、when if before until引導(dǎo)的從句 由一個(gè)主句和一個(gè)或多個(gè)從句構(gòu)成的句子叫復(fù)合句。主句是復(fù)合句的主干部分，從句是修飾主句或主句的某個(gè)成分的。從句不能單獨(dú)成句，但具有主語(yǔ)和謂語(yǔ)，須由關(guān)聯(lián)詞引導(dǎo)。根據(jù)從句在主句中充當(dāng)不同的成分，可分為不同的從句，例如，主語(yǔ)從句、賓語(yǔ)從句、表語(yǔ)從句、同位語(yǔ)從句、定語(yǔ)從句、狀語(yǔ)從句等。由when, if, before, until引導(dǎo)的從句一、when引導(dǎo)的時(shí)間狀語(yǔ)從句(1) when引導(dǎo)時(shí)間狀語(yǔ)從句時(shí)，表示“當(dāng)?shù)臅r(shí)候” when既可以指時(shí)間段也可指時(shí)間點(diǎn)Her brother was very fat when he was a child. 她哥

2、哥小時(shí)候很胖。They were talking when the teacher came in.老師進(jìn)來(lái)的時(shí)候，他們正在講話(huà)。 when從句中既可用延續(xù)性動(dòng)詞又可用非延續(xù)性動(dòng)詞You should keep your room clean and tidy when you live here.在你住在這里的時(shí)候，你應(yīng)該保持你房間干凈、整潔。When he arrives, hell tell us about the match.他回來(lái)的時(shí)候就會(huì)告訴我們比賽的情況。 when從句動(dòng)作既可和主句的動(dòng)作同時(shí)發(fā)生又可在主句的動(dòng)作之前或之后發(fā)生 Mary was doing her homewo

3、rk when her father was reading newspapers.瑪麗的爸爸在看報(bào)紙的時(shí)候她正在做作業(yè)。Ill call you when I get to the airport. 我一到機(jī)場(chǎng)就給你打電話(huà)。二、if引導(dǎo)的條件狀語(yǔ)從句條件狀語(yǔ)從句表示主句動(dòng)作發(fā)生的條件，條件有真實(shí)和非真實(shí)兩種。if引導(dǎo)條件狀語(yǔ)從句時(shí)，意為“如果，假如”，表示在某種條件下，某事很可能發(fā)生。if除了引導(dǎo)條件狀語(yǔ)從句，還可引導(dǎo)賓語(yǔ)從句。if引導(dǎo)的條件狀語(yǔ)從句和賓語(yǔ)從句的區(qū)別：（1）if 在句中的含義不同If 在賓語(yǔ)從句中翻譯為“是否”,相當(dāng)于whetherI want to know if he i

4、s a teacher.If 在條件狀語(yǔ)從句中翻譯為“如果”Ill go to see you if I am free next week.（2）if 在從句中的位置不同：If 引導(dǎo)的賓語(yǔ)從句放在主句之后，做賓語(yǔ)；而if引導(dǎo)的狀語(yǔ)從句可放在主句之前也可放在主句之后，If 引導(dǎo)的條件狀語(yǔ)從句放于句首時(shí)多用逗號(hào)隔開(kāi)I dont know if the train has arrived.I will go out tomorrow if it doesnt rain.= If it doesnt rain, I will go out tomorrow.（3） 時(shí)態(tài)要求上有區(qū)別1.I want

5、to know if there will be a sports meeting next month.If 引導(dǎo)的賓語(yǔ)從句的時(shí)態(tài)由主句及本身時(shí)態(tài)決定；2.If it rains , well hold it.If 引導(dǎo)條件狀語(yǔ)從句的時(shí)態(tài)為一般現(xiàn)在時(shí)， 記住“主將從現(xiàn)” 三、before和until引導(dǎo)的狀語(yǔ)從句（1）before表示“在 之前”，而until表示“直到才”，一般情況下，兩者可以互用。主句肯定表示主句動(dòng)作的終止時(shí)間，主句否定強(qiáng)調(diào)動(dòng)作的起始時(shí)間。1. 主句為否定時(shí)，謂語(yǔ)動(dòng)詞為非延續(xù)性動(dòng)詞。常見(jiàn)的動(dòng)詞有open, start, leave, go, arrive, finish,

6、 begin, stop, etc. 1) The noise of the street didnt stop before/until it was midnight.2) The children wont come back until/before it is dark.3) I didnt leave the lonely boy before/until his mother came home.2. 主句為肯定式，謂語(yǔ)為延續(xù)性動(dòng)詞。這類(lèi)動(dòng)詞有：stand, live, stay, talk, be, wait, etc.1). He lived with his parents

7、 until/before he graduated from school.2). I will wait before/until he comes to my help.3). I shall stay here until/before you come back.（2）下列情況下宜用before不用until.1、主句為肯定式，謂語(yǔ)為非延續(xù)性動(dòng)詞時(shí)只用before.1) He fell asleep before I could take off his clothes.2) We arrived there before it started to rain.3) The holi

8、day came to an end before I knew it.2、 主句謂語(yǔ)動(dòng)詞強(qiáng)調(diào)動(dòng)作的遲緩性，只用before，這時(shí)常伴有時(shí)間段狀語(yǔ)或時(shí)間段暗示。It was quite a long time before he found the elephant.過(guò)了很長(zhǎng)時(shí)間，他才找到大象。We had walked a long way before we found some water.走了很長(zhǎng)的路我們才找到水。It was midnight before my brother came home.我哥哥直到半夜才回來(lái)。3、 如果強(qiáng)調(diào)從句謂語(yǔ)動(dòng)作未發(fā)生就發(fā)生主句謂語(yǔ)動(dòng)作，只用befo

9、re,這時(shí)常譯為“未及（不等）就” 1)We can leave early in the morning before it gets too hot.趁天還不太熱，我們上午早點(diǎn)離開(kāi)。2)I must write it down before I forget it.趁我還未忘，我必須把它記下來(lái)。4、 表示“與其說(shuō)倒不如”,“與其毋寧”的意思時(shí)只用before.I would give up my job before I agree to be dismissed. 我與其被解雇還不如先辭職。He will die of hunger before he steals.他寧愿餓死也不愿意去

10、偷。5在某些特定句型中用before。It was (not) long before（不久）過(guò)了很長(zhǎng)時(shí)間才It will (not) be long before（不到）要過(guò)很長(zhǎng)時(shí)間才會(huì)It will probably not be long before they understand each other. 他們大概過(guò)不久就會(huì)互相了解。It was not long before the whole country rose up.不久全國(guó)人民就奮起反抗。（3）下列情況一般使用until1、主句是延續(xù)性謂語(yǔ)動(dòng)詞時(shí)，肯定,否定都可以，但意義完全不同，肯定表示動(dòng)作終止，而否定表示動(dòng)作開(kāi)始。F

11、or example:1).We discussed the problem until/before he came back. 我們一直討論到他回來(lái)。2).We didnt discuss the problem until he came back. 我們一直等他回來(lái)才討論問(wèn)題。2、Notuntil句型，盡管在某些情況下可與before互換使用，但在強(qiáng)調(diào)句中一般仍用until; 1). It was not until he told me that I knew it.直到他告訴我我才知道這件事。2).It was not until he finished his homework

12、that he went home.直到完成作業(yè)他才回家。3放于句首時(shí)用until. Until he finished his homework ，he didnt go home. 直到完成作業(yè)他才回家。應(yīng)注意：在使用not until時(shí)，若not until放于句首，句子應(yīng)部分倒裝。Not until he finished his homework，did he go home. 直到完成作業(yè)他才回家。四、when，if，until， before引導(dǎo)的狀語(yǔ)從句位置when , if和until引導(dǎo)的狀語(yǔ)從句放在主句前，也可放在主句后。但是放在主句前面時(shí)，須用逗號(hào) ，隔開(kāi)。而befor

13、e引導(dǎo)的狀語(yǔ)從句只能放在主句后面。I want to be a teacher when I grow up.= when I grow up， I want to be a teacher 五、when， if， until, before引導(dǎo)的狀語(yǔ)從句的時(shí)態(tài)用法在時(shí)間和條件狀語(yǔ)從句里，謂語(yǔ)動(dòng)詞通常用現(xiàn)在時(shí)態(tài)表示將來(lái)的動(dòng)作或狀態(tài)。I will write to you when I come back Guangzhou.n He didnt go to bed until his father came back yesterday.n He wont go to bed until hi

14、s father comes back today.n He doesnt go to bed until his father comes back every day.分析試題特點(diǎn)及做題思路考點(diǎn)：考連詞，考時(shí)態(tài)做題思路： 正確理解句子意思- 判斷語(yǔ)境提供的時(shí)態(tài)特點(diǎn)- 選擇正確的時(shí)態(tài)一、基礎(chǔ)題：1. When my mother returned last night, I _  a book. A. read   B. am reading   C. was reading  D. am going to read2. What

15、_ you _ when it began to rain?A. do, do   B. were, doing  C. are, doing  D. did, do3. I will go to the beach _ it doesnt rain this week.A. if B. and C. until D. when4. We wont leave here _ our teacher comes back.A. until B. since C. after D. as soon as5. Youll be late _ you dont get u

16、p early tomorrow morning.A. if B. when C. before D. until6. If he _ on time, we will go without himA. doesnt come B. dont comeC. didnt come D. wont come7. If you _ him tomorrow, please ask him if he _ to work on the farm with us.A. see ; goes B. will see; goes C. will see; will go D. see; will go8.

17、Difficulties are nothing if we _   not afraid of themA. will       B. shall           C. are        D. do9. Work hard if you  _    to get a good mark.A. wa

18、nted        B. wanting      C. want         D. will want10. If you _ to the party, youll have a great time. A. will go  B. went  C. go    D. going11. Ill wake you up when he _back.A. will &#

19、160; B. is going to come   C. comes    D. come12. If you _ tired, you _ to have a rest.A. feels, have B. feel, have C. felt, had D. is feeling, have 13. If there _ fewer trees, there _ more pollution.A. are, is B. will be, will be C. are, will be D. will be, are14. She went

20、to bed _ the TV play was over. A. until B. when C. and D. or15. I knew nothing about it _ he told me. A. and B. after C. or D. until 16. If she _ (get) up late, she _ (not catch) the early bus.A. gets, wont catch B. will get, doesnt catchC. get, wont catch D. get, catches 17. Were leaving for Shenzh

21、en _ it is fine today. A. as B. when C. if D. whether18. I was cooking _ she knocked at the door. A. because B. until C. before D. when19. It was raining heavily_ we got to Paris.A. while             B. if      

22、0;   C. when          D. because20 . The volleyball match will be put off if it_         . A. will rain       B. rains        C. rained 

23、0;  D. is raining提高題：1. I had to finish the picture _ my mother came back.A. until B. before C. after D. while2. I dont like to be interrupted if I_  . A. speak       B. will speak      C. am speaking    D. spoke3.

24、He was about to go to bed _ the doorbell rang.A. while B. as C. before D. when4. Where _ he _ the film if he has time?A. does, see B. do, see C. will, see D. are, see5. _ they _a match when the P.E. teacher was busy?A. Are, having B. Do, have C. Will, have D. Are, have6. I havent heard from him _ he

25、 left home. A. before B. when C. until D. because7. Take the medicine _ you go to bed. A. before B. after C. until D. because8. I wont believe it _ I hear with my own ears.A. until B. after C. because D. when9. She likes everything to be in place _ she starts to work.A. before B. after C. until D. b

26、ecause10. He always stay in bed _ lunch time.A. before B. after C. until D. because11. I dont like to be interrupted if I_  . A. speak       B. will speak       C. am speaking    D. spoke12. If you _  the book

27、you will understand the story better.A. will be reading    B. have read     C. will have read    D. read13. If you _  I will go with you.A. go to          B. went        

28、   C. will       D. should go14. If he_ exercise, he_healthy.A. not; will                     B. isnt; wont beC. doesnt; will be      &

29、#160;       D. doesnt do; wont be15. If he _  , I  _ go swimming alone.A. doesnt come will go          B. wont come; will goC. will come; wont go          

30、 D. is coming; dont go難題：1. I dont know _ he is at home now.A. before B. when C. or D. if2. It will be a long time _ Peter _ his work. A. since, has finished   B. after, finishes  C. when, will finish   D. before, finishes.3 I _ her the answer if she _me.A. can tell, will ask   B. will tell, will ask  C. would tell, ask   D. will tell, asks4. It was quiet _ those big trucks started coming through the town.A. before B. after C. until D. unless 5. It seemed only seconds _ the boy finished washing his