before的用法总结(2)

时间:2020-9-23 作者:admin

  二、掌握热点句型用法

  It was not long before…(过去)没过多久就……

  It was not long before he returned to Beijing. 不久他就回到北京。

  需要特别注意,该句型可以进行创新,可将否定句改为肯定句(It was long before…过了很久才……)或将一般过去时改为一般将来时(It will not be long before…要不了多久就……;It will be long before…要过很久才……)。before在这些句型中均引导时间状语从句, long这个抽象的时间也可改为years, weeks, days等具体表时间的词。

  It was long before he married Wei Fang. 过了很久他才娶魏芳。

  It will be long before he goes abroad. 要过很久他才出国。

  Will it be years before he goes to school? 要过好几年他才能上学吗?

  高考题例:

  It ________ long before we ________ the result of the experiment.

  A. will not be…will know B. is…will know C. will not be…know D. is…know

  【析】正确答案为C。该句面意思为:在我们知道实验结果之前不会过很长一段时间,也就是不会过很长一段时间我们就会知道实验结果。应使用It was not long before的创新句型It will not be long before,before引导时间状语从句时,从句应用一般现在时代替一般将来时。

  Scientists say it may be five or six years ________ it is possible to test this medicine on human patients.

  A. since B. after C. before D. when

  【析】正确答案为C。该句型也是It was not long before的创新句型。

  when与befor的区别

  本文结合典型例题来归纳一下before的特殊用法。

  before作为连词时的基本意义是“在……之前”,用于表示时间或顺序。如:Turn the light off before you sleep. (睡前先把灯熄掉。) Think before you speak. (说话之前,应先想清楚。) 但在不同的语境中before有不同的意义:

  1. before表示“不等……就……”、“尚未……就……”

  例1: —Why didn’t you tell him about the meeting? (2006年四川)

  —He rushed out of the room I could say a word.

  A. before B. until C. when D. after

  解析: 答案为A。题中before意为“不等……就”、“尚未……就……”,它表示从句的动作尚未来得及发生,主句的动作已发生或完成。全句句意为:我还没来得及说他就冲出了房间。又如:

  Before I could get in a word, he had measured me. 我还没有来得及插上话,他就给我量好了尺寸。

  The phone stopped ringing before I answered it. 我还没有来得及接,电话就挂了。

  2. before表示“不知不觉,还没弄清就……”(常用于before sb. know/realize…)

  例2: Several weeks had gone by I realized the painting was missing. (2004全国)

  A. as B. before C. since D. when

  解析: 此题最易错选C或D项,而正确答案为B。用since则时间延续到了现在,在时间上与had gone矛盾;用when则无法强调时间流逝的不知不觉性。又如:

  Time passed quickly and three months went by before I knew it. 时间飞快地流逝,不知不觉3个月过去了。

  3. before表示“以免,不然”

  例3: It’s cloudy. Take an umbrella you regret it.

  A. but B. and C. after D. before

  解析: and及but表示并列关系,不合语境;after意为“在……之后”,不合常识,应是在下雨前带伞;before在此处意为“以免你后悔”。before作此意义的用法的例子不少,又如:

  Put that away before it gets broken. 把它收好,以免砸了。

  Do it before you forget. 尽早动手,不然忘了。

  4. before用于it was / will be + 时间 + before … 句型中。

  例4: It won’t be long you regret what you have done.

  A. after B. before C. since D. until

  解析: It was / will be + 时间 + before … 表示“过了多久才…(强调时间的长)”,在否定句中则表示“没过多久就…(强调时间的短)”。例如:

  It will be two years before we meet again.我们要过两年才能见面。

  It wasn’t long before he married again. 不久他就又结婚了。

  We didn’t wait long before he came back. 我们没等多久他就回来了。

  5. before表示“与其……宁可……,比……优先”(用于表优先顺序)

  例5: They would fight to death they surrendered(投降).

  A. before B. after C. since D. because

  解析: 答案为A。before引导的从句在与will, would连用时,有“宁愿……也不”的含义。before即使是作介词用也有此意义。例如:

  True men choose death before dishonor. 大丈夫宁可杀不可辱。

  I’d die before I apologize to them! 我宁死也不愿向他们道歉!

  We will die before we give in. 我们宁死不屈。

  6. before表示“……才”(强调从句动作发生得晚或慢)

  例6: They sailed along the Pacific Ocean for two weeks they arrived home.

  A. since B. when C. before D. after

  解析: 此题正确答案为C。全句句意为:“他们在太平洋航行了两个星期才回到家。”强调从句动作比主句动作发生晚。又如:

  I thought carefully about it before I made a decision. 我经过再三考虑才决定。

  It may be many years before the situation improves. 或许要过很多年这种状况才能得到改善。

  下面有一道2003年的高考题:

  Don’t be afraid of asking for help ____ it is needed.

  A. unless B. since C. although D. when

  本题答案为D,考查when作连词的用法。此处when相当于if,意为“如果,要是”。

  下面我们来归纳一下when 的用法:

  1.作疑问副词,意为“什么时候,什么场合”。如:

  I don’t know when he died.

  我不知道他何时去世的。

  Since when has he been missing?

  他是从什么时候失踪的?

  2.作关系副词,引导定语从句。如:

  He came at a time when we needed help.

  他在我们需要帮助的时候来了。

  We’ll never forget the day when we joined the Party.

  我们永远不会忘记我们入党的那一天。

  3.作连词,引导时间状语从句。如:

  ①表示“当……的时候”、“无论什么时候”、“一……的时候”之意。如:

  It was raining when we arrived.

  我们到的时候天正在下雨。

  When I was a boy, I used to go to the Western Hills on Sundays.

  小时候,我经常在星期天到西山公园去玩。

  It is cold when (whenever) it snows.

  一下雪天就冷。

  He joined the PLA when (as soon as) he returned home.

  他回家后就参了军。

  ②意为“可是,然而,既然,考虑到”。如:

  How can they learn anything when they spend all their spare time watching television?

  他们把所有的空闲时间都用来看电视了,还能学什么东西呢?

  They have only three copies when we need five.

  他们只有三本,可我们需要五本。

  The waitress brought me coffee when I asked for tea.

  虽然我叫了茶,女服务员却拿了咖啡给我。

  ③ 意为“如果,要是”。如:

  You shall have the apple when you say “Please”.

  你要是说“请”,这苹果就是你的。

  He will likely recover when he undergoes the operation.

  如果动手术的话,他可能会复元。

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