時間狀語從句(完整版)

1、21時間狀語從句 引導(dǎo)時間狀語從句的五類引導(dǎo)詞一引導(dǎo)時間狀語從句的從屬連詞(以下稱引導(dǎo)詞)很多，為方便記憶，現(xiàn)作以下分類：1. 基本類包括before, after, when, while, as, since, till, until, once, as soon as 等。如：Did anyone call when I was out? 我不在家時誰來過電話嗎?We have known each other since we were children. 我們從小認(rèn)識。Youll feel better after you take the pills. 吃完藥丸后你會感到好一些。M

2、ake sure that all the lights are off before you go to bed. 睡覺前一定要關(guān)燈。Dont promise him anything till weve had time to think about it. 在我們有時間考慮之前別答應(yīng)他什么。2. 名詞類即由名詞詞組充當(dāng)引導(dǎo)詞，包括the moment, the minute, the second, the instant 等(均表示“一就”。如I loved you the instant (that) I saw you. 我一見到你就愛上你了。Tell me the moment

3、(that) you get the results. 你一拿到結(jié)果就給我打電話。3. 副詞類即由副詞充當(dāng)引導(dǎo)詞，如 immediately, directly, instantly等。如：I came immediately you called. 你一打電話我就來了。Directly I walked in the door I smelt smoke. 我一進(jìn)門就聞到煙味。4. 短語類主是幾個涉及time短語，如every time，each time，(the) next time，any time，the last time，the first time 等。如：Next time

4、you come in, please close the door. 下次你進(jìn)來，請關(guān)門。My roof leaks every time it rains. 每次下雨，我的房頂就漏。He felt nervous each time she spoke to him. 每次她和他講話，他都感到緊張。The last time we talked he said he needed another two days. 上次我們談話時他說他還需要兩天。5. 句型類包括no soonerthan, hardlywhen 等。如：I had no sooner closed the door th

5、an somebody knocked. 我剛把門關(guān)上就有人敲門。Hardly were the words uttered when he began to regret them. 話剛說出口他就開始后悔了。二時態(tài)呼應(yīng)在時間狀語從句中，不能用一般將來時、過去將來時態(tài)或?qū)硗瓿蓵r，而要用相應(yīng)的一般現(xiàn)在時態(tài)、一般過去時或現(xiàn)在完成時來代替。如：Ill telephone you as soon as I get there. 我一到達(dá)那里就打電話給你。She said she would phone me as soon as she got there. 她說她一到達(dá)那里就給我電話。Dont

6、get off the bus until it has stopped. 等車停穩(wěn)后才下車。I will tell you after they leave. 于他們走后我再告訴你。I waited till/until she was back. 我一直等到她回來Once time is gone, you will never get it back. 時間一旦失去就再也得不到了1. 時態(tài)呼應(yīng)一般來講，復(fù)合句都要遵循主、從句時態(tài)呼應(yīng)規(guī)律，狀語從句也不例外。即主句用現(xiàn)在時，從句也用現(xiàn)在時；主句用過去時，從句也用過去的某種時態(tài)。如：Be careful when you cross the

7、road. 過馬路時要小心。You must see the doctor if you are ill. 如果你生病了，你必須去看醫(yī)生。主句是一般過去時，從句也要用一般過去時。如：When he was seven years old, he could swim. 當(dāng)他七歲時就會游泳。She turned off the light before she left the office. 她離開辦公室前就關(guān)了燈。與時間狀語從句有關(guān)的時態(tài)問題關(guān)于這個問題有兩點(diǎn)值得注意：(1) 當(dāng)主句為將來時態(tài)或具有將來意義時，時間狀語從句通常要用一般現(xiàn)在時表示將來意義，而不能直接使用將來時態(tài)：Turn of

8、f the lights before you leave. 走前關(guān)燈。I will tell him as soon as he arrives. 他一來我就告訴他。(2) 與since 從句搭配的主句的時態(tài)通常是現(xiàn)在完成時態(tài)：He has lived here since 1999. 自1999年以來，他就一直住在這兒。Where have you been since I last saw you? 自我上次見到你之后你到哪里去了?【注】在特定的語言環(huán)境中有時也可能用過去完成時或一般現(xiàn)在時：It seems like years since we last met. 我們似乎幾年未見面了

9、。Yesterday he told me that he hadnt eaten anything since Tuesday. 他昨天告訴我自星期二以來他一直未吃任何東西。2. 主從句的位置。大多數(shù)情況下，從句可以位于主句之前，也可以位于主句之后。不過從句在前時，主從句之間必須用逗號隔開。如：Please tell me when he comes back. = When he comes back, please tell me.三基本類（一）. when, while, as的用法when只能用于一般時態(tài)， while可以用于進(jìn)行時態(tài)while從句中的謂語動詞必須是延續(xù)性動詞；表示帶

10、有規(guī)律性的“每當(dāng)”或當(dāng)主、從句謂語動詞的動作發(fā)生有先后時，只能用 when；當(dāng)表示“一邊一邊”或“隨著”時，只能用 as。另外，用于此義的 as 所引導(dǎo)的時間狀語從句謂語只能是動作動詞，不能是狀態(tài)動詞。例題：_ John was watching TV, his wife was cooking.A. As B. As soon as C. While D. Till第一次描述： 三者可表示“當(dāng)時候”，區(qū)別如下：(1) 若主句表示的是一個短暫性動作，從句表示的是一個持續(xù)性動作，三者都可用：He fell asleep when while, as he was reading. 他看書時睡著了

11、。【注】as 用于引出一個持續(xù)性動詞表示“在期間”時，其謂語通常只能是那些含有動作(action)和發(fā)展(development) 意味的動詞，一般不能是那些不用于進(jìn)行時態(tài)的動詞(如 be, seem, love, want, agree, see, know, have 等)，所以下面一句中的 while 不能換為 as：A：Im going to the post office. 我要去郵局。B：While youre there, can you get me some stamps? 當(dāng)你在郵局時，能幫我買幾張郵票嗎?(2) 若主、從句表示兩個同時進(jìn)行的持續(xù)性動作，且強(qiáng)調(diào)主句表示的動作

12、延續(xù)到從句所指的整個時間，通常要用 while：Dont talk while youre eating. 吃飯時不要說話。I kept silent while he was writing. 在他寫的時候，我默不作聲。但是，若主從句表示的兩個同時進(jìn)行的動作含有“一邊一邊”之意思，通常用 as：She sang as she went along. 她邊走邊唱。(3) 若從句是一個短暫性動作，主句是一個持續(xù)性動作，可用 as / when 但不用 while：It was raining hard when as we arrived. 我們到達(dá)時正下著大雨。(4) 若主從句表示的是兩個同時

13、(或幾乎同時)發(fā)生的短暫性動作，用 as / when：I thought of it just when as you opened your mouth. 就在你要說的時候，我也想到了。(5) 若要表示兩個正在發(fā)展變化的情況，相當(dāng)于漢語的“隨著”，一般用 as：Things are getting better and better as time goes on. 隨著時間的推移，情況越來越好。As it grew darker, it became colder. 天色越晚，天氣越冷。(6) 表示“每當(dāng)?shù)臅r候”(暗示一種規(guī)律性)，一般要用 when：Its cold when it s

14、nows. 下雪時天冷。He smiles when you praise him. 你夸獎他時他總是笑笑。(7) 若主從句所表示的動作不是同時發(fā)生，而是有先后順序時，一般要用 when：I will go home when he comes back. 他回來時，我就回家去。(8) when 可用作并列連詞，表示“這時(突然)”；while 也可以用作并列連詞，表示“而”、“卻”(表示對比)；但 as 則沒有類似用法：We were about to start when it began to rain. 我們正要出發(fā)，這時天開始下雨了。He likes coffee, while sh

15、e likes tea. 他喜歡咖啡，而她卻喜歡茶。(9) as 和 when 后均可直接跟一個名詞，構(gòu)成省略句，但 while 一般不這樣用：As When a boy, he lived in Japan. 他小時候在日本。(10) when 和 while后可接現(xiàn)在分詞、介詞短語、形容詞等構(gòu)成省略句，但as 一般不這樣用：When While reading, he fell asleep. 他看書時睡著了。When While in trouble, ask her for help. 遇到麻煩的時候你就去找她幫忙。第二次描述：as, while ,when 的用法as， while和

16、when均可用作從屬連詞，引導(dǎo)時間狀語從句，作“當(dāng)時候”解。它們所引導(dǎo)的時間狀語從句有時意思一樣，這三個詞可以互換使用；有時卻有差異，則不能互換。 一、 as的意思是“正當(dāng)時候（just as，at the same moment that）”“隨著(while，when)”,它既可表示一個具體的時間點(diǎn)，也可以表示一段時間。as可表示主句和從句的動作同時發(fā)生或同時持續(xù)，即“點(diǎn)點(diǎn)重合”“線線重合”；又可表示一個動作發(fā)生在另一個動作的持續(xù)過程中，即“點(diǎn)線重合”，但不能表示兩個動作一前一后發(fā)生。如果主句和從句的謂語動詞都表示持續(xù)性的動作，二者均可用進(jìn)行時，也可以一個用進(jìn)行時，一個用一般時或者都用一般

17、時。例如： 1. As I got on the bus， he got off. 我上車，他下車。（點(diǎn)點(diǎn)重合） 2. He was writing as I was reading. 我看書時，他在寫字。（線線重合） 3. The students were talking as the teacher came in. 老師進(jìn)來時，學(xué)生們正在講話。（點(diǎn)線重合） 二、while的意思是“在同時（at the same time that )”“在期間(for as long as, during the time that）”。從while的本身詞義來看，它只能表示一段時間，不能表示具體的時

18、間點(diǎn)。在時間上可以是“線線重合”或“點(diǎn)線重合”，但不能表示“點(diǎn)點(diǎn)重合”。例如： 1. He was watching TV while she was cooking. 她做飯時，他在看電視。（線線重合） 2. He was waiting for me while I was working. 我工作的時候，他正等著我。（線線重合） 3. He asked me a question while I was speaking. 我在講話時，他問了我一個問題。（點(diǎn)線重合） 三、 when的意思是“當(dāng)時候（at the time that）”“無論什么時候（whenever）” “一就（as s

19、oon as ）” “在以后（after）”。它表示的時間概念比較廣泛，上述例句中的as或while均可用when代替，因?yàn)閣hen不但可以表示具體的時間點(diǎn)，而且也可以表示一段時間。在時間上它既能表示“點(diǎn)點(diǎn)重合”“線線重合”，又能表示“點(diǎn)線重合”。例如： 1.When he came in， she went out.他進(jìn)來，她出去。（點(diǎn)點(diǎn)重合） 此句中when從句的動作表示的是一個時間點(diǎn)，when可以用as代替，但不能用while代替。 2. When he came back， I was doing some washing. 他回來時，我在洗衣服。（點(diǎn)線重合） 此句中when從句的動作

20、表示的是一個時間點(diǎn)，所以只能用as代替，不能用while代替。 3. When Mary was writing a letter, the children were playing outside. 瑪麗寫信時，孩子們都在外面玩。（線線重合） 此句中的when從句的動作表示的是一段時間，故可用as 或 while代替習(xí)題：1. Henry is in charge of the office _ Mr. Smith is away.2. I saw her just _ she was getting off the train.3. Have a good look at that ma

21、n _ you pass him.第三次描述when,as,while這三個詞都可以引出時間狀語從句，它們的差別是：when 從句表示某時刻或一段時間 as 從句表示進(jìn)展過程，while 只表示一段時間When he left the house, I was sitting in the garden.當(dāng)他離開家時，我正在院子里坐著。When he arrived home, it was just nine oclock.當(dāng)他到家時，正是九點(diǎn)鐘。As he grew older, he became more intelligent.隨著他年齡的增長，他變得更有才智了。While he w

22、as in London,he studied music.當(dāng)他在倫敦時，他學(xué)習(xí)音樂。While she was typing the letter,the telephone rang.當(dāng)她在用打字機(jī)打那封信時，電話響了。when意為在時刻或時期，它可兼指時間點(diǎn)與時間段，所引導(dǎo)的從句的動詞既可以是終止性動詞，也可是持續(xù)性動詞。如： When I got home, he was having supper.我到家時，他正在吃飯。 When I was young, I liked dancing.我年輕時喜歡跳舞。 while只指時間段，不指時間點(diǎn)，從句的動詞只限于持續(xù)性動詞。如： Whil

23、e I slept, a thief broke in.在我睡覺時,盜賊闖了進(jìn)來。 辨析 when從句與主句動作先后發(fā)生時，不能與while互換。如： When he has finished his work, he takes a short rest.每當(dāng)他做完工作后，總要稍稍休息一下。(when = after) When I got to the cinema, the film had already begun.當(dāng)我到電影院時，電影已經(jīng)開始了。(when=before) when從句動詞為終止性動詞時，不能由while替換。如： When he came yesterday, w

24、e were playing basketball.昨天他來時，我們正在打籃球。 當(dāng)從句的謂語是表動作的延續(xù)性動詞時，when, while才有可能互相替代。如： While / When we were still laughing, the teacher came in.正當(dāng)我們?nèi)栽诖舐曟倚r，老師進(jìn)來了。 當(dāng)從句的謂語動詞是終止性動詞，而且主句的謂語動詞也是終止性動詞時,when可和as通用，而且用as比用when在時間上更為緊湊，有正當(dāng)這時的含義。如： He came just as (or when) I reached the door.我剛到門那兒，他就來了。 從句的謂語動詞如

25、表示狀態(tài)時，通常用while。如： We must strike while the iron is hot.我們應(yīng)該趁熱打鐵。 while和when都可以用作并列連詞。 Mike is tall while his brother is short.邁克的個子很高，然而他弟弟很矮。 Mary was on her way home when two big boys stopped her.瑪麗正走在回家的路上，這時兩個大個子男孩攔住她。例題：“Im going to the post office.” “_ youre there, can you get me some stamps?”

26、A. As B. While C. Because D. If 第四次描述 ： while與when以及as之間的區(qū)別。1. 當(dāng)從句中的謂語動詞是持續(xù)性的動作時,我們可以用while, when或as。While / When / As I was walking down the street, I noticed a police car in front of the bank. 我順著馬路往前走時,發(fā)現(xiàn)銀行門前停著一輛警車。2. 當(dāng)從句中的謂語動詞表示瞬間動作時,不可用while。He was on the point of leaving when someone knocked a

27、t the door. 他正要走,這時有人敲門。3. 如果談?wù)搩蓚€長動作,最常用的是while。While John was sitting biting his nails, I was working out a plan to get us home. 約翰坐在那里咬指甲時,我想出了一個回家的辦法。不過, as是可以用來說明兩種正在發(fā)展或變化的情況的,這時as引導(dǎo)一個持續(xù)性的動作,主句中的動作與之同時進(jìn)行。As we talked on, he got more and more excited. 我們繼續(xù)往下談的時候,他越來越興奮。4. 如果表示兩個短動作或事件同時發(fā)生,最常用的是as

28、或just as,也可用when。Just as he caught the ball, there was a tearing sound. 當(dāng)他抓住球的時候,有一種撕裂的聲音。I thought of it just when you opened your mouth. 就在你要說話的時候,我也想到了。as引導(dǎo)時間狀語從句的謂語特點(diǎn)as 引導(dǎo)時間狀語從句表示“當(dāng)?shù)臅r候”“在期間”時，該從句的謂語通常是那些表示動作意義的動詞，而不能是be(是、在), have(有)，like(喜歡)，belong(屬于)等表示狀態(tài)或靜態(tài)意義的動詞。我打算去郵局。當(dāng)你在郵局的時候，請幫我買幾張郵票好嗎?誤：

29、Im going to the post office.As you are there, can you get me some stamps?正：Im going to the post office.While you are there, can you get me some stamps?正因?yàn)?as 引導(dǎo)時間狀語從句表示“當(dāng)?shù)臅r候”“在期間”時，從句的謂語不能是表示狀態(tài)或靜態(tài)意義的動詞，所以當(dāng)下面第一句變?yōu)榈诙溥@樣的狀語從句時，不能再用 as，而應(yīng)用 when：As a student he had known great poverty.When he was a stude

30、nt he had known great poverty. 他當(dāng)學(xué)生時，經(jīng)歷過很貧困的生活。但是，當(dāng) as 引導(dǎo)原因狀語從句時，其謂語動詞可以是狀態(tài)或靜態(tài)動詞。如：As there was very little support, the strike was not successful. 由于支持的很少，罷工未獲成功。As I was anxious to please him, I bought him a nice present. 因?yàn)槲壹庇谟懞盟?，我給他買了一件精美禮品。As there isnt anything more to do, I may as well go hom

31、e early 既然這里沒有別的事要做，我還不如早點(diǎn)回家。while的用法可從下述幾點(diǎn)理解與運(yùn)用。一、while意為“當(dāng)時候”,指一段時間,不能用來表示一個時間點(diǎn)。While the discussion was still going on, George came in. 當(dāng)討論還在進(jìn)行時,喬治走了進(jìn)來。二、while意為“而;然而”,表示轉(zhuǎn)折。Therere plenty of rain in the southeast, while theres little in the northeast. 東南部雨量充足,而西北部則很少下雨。三、while意為“雖然;盡管”,表示讓步。While

32、 I admit his good points, I can see his shortcomings. 盡管我承認(rèn)他的優(yōu)點(diǎn),但我還是能看到他的缺點(diǎn)。四、while意為“只要”,表示條件。We can surely overcome these difficulties while we are closely united. 只要我們緊密地團(tuán)結(jié)一致,一定能克服這些困難。五、while從句中的省略。當(dāng)while從句中的主語與主句的主語一致,且含有be的某種形式時,從句中的主語連同be可同時省略。While listening to the radio, she fell asleep. 她在

33、聽收音機(jī)時睡著了。While in London, he studied music and painting. 在倫敦時,他學(xué)習(xí)音樂和繪畫。六、while可用作名詞,意為“一會兒;一段時間”。作名詞用時,主要用于短語中: after a while “過了一會兒”; all the while “一直,始終”; a short / little while ago “剛才”; once in a while “偶爾,間或”; wait / rest(for) a while “等 / 休息一會兒”。I havent seen her for a long while.我好久沒有看見她了。Wh

34、ere have you been all this while?這一陣子你到哪去了?He usually goes to work by bike, but once in a while he goes by bus.他通常騎自行車上班,但偶爾也乘公共汽車。I looked everywhere for the letter, but it was in my pocket all the while. 我到處找那封信,卻不知它一直在我口袋里。when 和while的用法區(qū)別when是at or during the time that, 既指時間點(diǎn)，也可指一段時間； while是duri

35、ng the time that，只指一段時間，因此when引導(dǎo)的時間狀語從句中的動詞可以是終止性動詞，也可以是延續(xù)性動詞，而while從句中的動詞必須是延續(xù)性動詞。 when 說明從句的動作和主句的動作可以是同時，也可以是先后發(fā)生；while 則強(qiáng)調(diào)主句的動作在從句動作的發(fā)生的過程中或主從句兩個動作同時發(fā)生。 由when引導(dǎo)的時間狀語從句，主句用過去進(jìn)行時，從句應(yīng)用一般過去時；如果從句和主句的動作同時發(fā)生，兩句都用過去進(jìn)行時的時候，多用while引導(dǎo)，如： a. When the teacher came in, we were talking. 當(dāng)此句改變主從句的位置時，則為：While

36、we were talking, the teacher came in. b. They were singing while we were dancing. when和while 還可作并列連詞。when表示“在那時”；while表示“而，卻”，表對照關(guān)系。如： a. The children were running to move the bag of rice when they heard the sound of a motor bike. 孩子們正要跑過去搬開那袋米，這時他們聽到了摩托車的聲音。 b. He is strong while his brother is wea

37、k. 他長得很結(jié)實(shí)，而他弟弟卻很瘦弱。when只能用于一般時態(tài)， while可以用于進(jìn)行時態(tài)when 在絕大多數(shù)情況下，所引導(dǎo)的從句中，應(yīng)該使用非延續(xù)性動詞（也叫 瞬間動詞）例如：Ill call you when I get there. 我一到那里就給你打電話 I was about to go out when the telephone rang.我剛要出門，電話鈴就響了。但是，when 卻可以 be 連用。例如：I lived in this village when I was a boy. 當(dāng)我還是個孩子的時候我住在這個村莊里。 When I was young, I was s

38、ick all the time. 在我小時候我總是生病while 當(dāng).的時候 While he was eating, I asked him to lend me $2. 當(dāng)他正在吃飯時,我請他借給我二美元。While I read, she sang. 我看書時，她在唱歌。while 的這種用法一般都和延續(xù)性動詞連用while 可以表示“對比”這樣用有的語法書認(rèn)為是 并列連詞 Some people like coffee, while others like tea. 有些人喜歡咖啡, 而有些人喜歡茶。as和just as的區(qū)別是：as有多種詞性，just as只有一種詞性，就是副詞。

39、但是意思上是很接近的。as 當(dāng).之時 ，一邊.一邊.He dropped the glass as he stood up. 他站起來時，把杯子摔了。She sang As she worked. 她一邊工作一邊唱歌。just as 正像，就像，就.的樣子例如：It is just as you said. Leave exerything just as you find it.一般來說 as 后面即可以跟延續(xù)性動詞，也可以跟非延續(xù)性動詞。1）as,when引導(dǎo)短暫性動作的動詞。Justas/Justwhen/When I stopped mycar, a man came up to me

40、.2）當(dāng)從句的動作發(fā)生于主句動作之前，只能用when引導(dǎo)這個從句，不可用as或while。When you have finished your work, you may have a rest.3）從句表示隨時間推移連詞能用as，不用when或while。As the day went on, the weather got worse.until /和till既可用作介詞也可用作連詞，引導(dǎo)狀語。通常有以下幾種用法： 一、 用于肯定句作“直到為止”解時，主句的動詞一般是延續(xù)到until / till所表示的時間為止。例如： 1. He waits until / till the chil

41、dren are asleep. 他等著直到孩子們睡熟。 2. I shall stay here until / till twelve oclock. 我將留在這里一直到十二點(diǎn)鐘。 二、 用于否定句作“在以前”、“直到才”解時，主句的動詞一般是非延續(xù)性的，它所表示的動作直到until / till 所表示的時間才發(fā)生。例如： 1. He didnt come until / till late in the morning. 他直到早上很遲才來。 2. He didnt arrive until / till the game had begun. 直到比賽開始他才到。 注意：主句為一般將

42、來時，until / till引導(dǎo)的從句用一般現(xiàn)在時代替將來時。例如： He couldnt ride until / till he was fifteen years old. 他直到十五歲才會騎自行車。 三、 用于“not.until.”的句式可以轉(zhuǎn)換成when 或after引導(dǎo)的時間狀語從句，但主句必須要用肯定形式。例如： 1. They didnt get off until the train came to a complete stop.=They got off after the train came to a complete stop. 火車停了他們才下車。 2. Th

43、e student wont come into the classroom until the teachers finish their work.=The students will come into the classroom when the teachers finish their work. 當(dāng)老師們完成工作時，學(xué)生們將走進(jìn)教室。 四、 用于延續(xù)性動詞的肯定或否定句中，但含義不同。例如： 1. The meeting continued until / till 7:00. 會議一直開到七點(diǎn)。 2. We didnt have the meeting until /till

44、7:00. 直到七點(diǎn)我們才結(jié)束會議。 五、 用于“It is / was not until.that”或含有“not.until.”的強(qiáng)調(diào)結(jié)構(gòu)中，其中的until不能改為till。不可替換。例如： 1. It was not until the film had begun that he arrived. 直到電影開始他才到。 2. It is not until 8:00 that we begin our class every day. 我們每天八點(diǎn)開始上課。 六、 Not until放在句首時，句子要倒裝，其中的until不能改為till 。例如： 1. Not until the

45、 last moment did he change his mind. 直到最后一刻他才改變主意。 2. Not until midnight did it stop raining. 直到午夜雨才停。 七、 句首通常只用until,不用till。例如： 1. Until then, I knew nothing at all about it. 在那之前，我對此事一無所知。 2. Until you told me I had no idea of it. 在你告訴我之前，我對此一無所知。 八、 某些固定詞組或諺語中通常只用till。例如： 1. from morning till nig

46、ht 從早到晚。 2. up till now直到現(xiàn)在英美國家的英語語法教師是這樣來描述這兩個字的分別的：“Till” is used to mean the time up to a particular instance and the action can continue even after that.“Until” is used to mean the time up to a particular instance and the speaker has in mind that the action after this time does not almost happen

47、.翻譯：Till是指直到某一特定事件發(fā)生的時候，而在那個時刻之后，該事情或狀況仍將持續(xù)。Until是指直到某一特定事件發(fā)生的時候，而講話的人在自己心里認(rèn)為，在那個時刻之后，該事情或該狀況將中止（不怎么可能持續(xù)）。Till 和Untill 的用法區(qū)別在很多情況下，這兩個詞是這可以互換使用的，也就是說，這兩個詞的意思非常相近。一般而言，till 用于肯定句，untill 用于否定句。但是，這兩個詞在意義上也是有細(xì)微差別的。對till/until從句的理解1. 主句為肯定式，主句謂語動詞必須為持續(xù)性動詞，且該動詞所表示的動作或狀態(tài)一直延續(xù)到 until / till 從句所表示的時間為止，可譯作“（

48、直）到”。如：He waited until/till I returned. 他一直等到我回來。2. 主句為否定式（包括含 no, nobody, nothing, never, hardly, little 等否定詞的肯定句），若主句謂語動詞是非持續(xù)性動詞，則該動詞所表示的動作在 until / till 從句表示的時間開始發(fā)生。一般先譯從句“直到”，后譯主句，not 譯成“才”，即“直到才”。如：His mother didnt leave until/till he was asleep. 直到他睡著了，他母親才離開。Nobody can leave until/till the me

49、eting is over. 直到散會才能離開。3. 主句為否定式，若主句謂語動詞是持續(xù)性動詞，則須根據(jù)上下文去理解until/till從句的含義，一般譯為“直到才”或“沒有到”。如：He didnt wait until/till I returned. 他沒有等到我回來。She didnt sleep until/till I returned. 她直到我回來才睡著。,until直到時候; notuntil直到才You are to stay here until / till your mother comes back.The meeting was put off until ten

50、 oclock.Not until we watched the Earth Day program on TV did we know much about global warning.= We did not know much about global warning until we watched the Earth Day program.= It was not until we watched the Earth Day program on TV that we knew much about global warming.Not until he failed in th

51、e exam did he realize that he had wasted much time playing computer games.not .until 引導(dǎo)時間狀語從句，從句不能用將來時，主句是一般將來時，從句用現(xiàn)在時。Dont get off the bus until it stops.(主句是祈使句從句用現(xiàn)在時）He didnt go to bed until his mother came back.（主句是過去時，從句時態(tài)一致）He wont call you until he finishes his work.(主句用一般將來時，從句用現(xiàn)在時對before從句的

52、理解before的本意為“在之前”，根據(jù)具體語境還可理解為“還沒來得及/還沒有就，趁著還沒就，不知不覺就，才”等。如：I had not sat long before he came back. 我沒坐多久他就回來了。He almost knocked me down before he saw me. 他幾乎把我撞倒才看到我。Before I could get in a word, he measured me. 我還來得及插話，他就給我量好了尺寸。Ill water the flowers before it gets dark. 我要趁著天還沒黑把花澆好水。Be a pupil be

53、fore you become a teacher. 先做學(xué)生，后做先生。Time passed quickly and three months went by before she knew it. 時間過得飛快，她不知不覺就在那里度過了三個月。I will die before I will betray my country. 我寧可死也不會背叛我的國家。after表示主句動作發(fā)生在從句動作之后，主句和從句的時間關(guān)系正好與before相反。如：It will be four days before they come back.他們要過四天才能回來。My father had left

54、 for Canada just before the letter arrived.我父親恰好在信到達(dá)之前去加拿大了。After you think it over, please let me know what is your decision.你仔細(xì)考慮過之后，告訴我你是怎樣決定的。After we had finished the work, we went home.完成工作之后，我們回家了。before 與untill的區(qū)別It is not A .before B在B之前A是完成不了的 It is not A untill B 直到B， A 才完成 一個是到了B沒完成一個是到了

55、B完成了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 that he went home.直到完成作業(yè)他才回家。.而且與UNTIL主句的動詞一定不是短暫性的動詞,是可以有延續(xù)性的動詞,比如come,go,open等是不會和UNTIL用在一起的.It is three years since I joined the Party. 我入

56、黨有三年了。It is three years since he lived here. 他不住這里有三年了。It will be years before we meet again. 要過幾年之后我們才能重相聚。It was not long before he came back. 沒過多久他就回來了。It was evening before they got here. 他們到達(dá)這里之前就已天夜了。It was five oclock when he got home. 他回到家時已是五點(diǎn)了。(比較強(qiáng)調(diào)結(jié)構(gòu)：It was at five oclock that he got home. )since的用法1) since +過去一個時間點(diǎn)(如具體的年、月、日期、鐘點(diǎn)、19