before用法知多少？

before用法知多少？

在高考中，状语从句是每年高考单项填空部分必考的题目之一，考查的重点是考生容易混淆并且近似的连词在逻辑行文和语篇结构中的使用。before作连词的用法一直是高考的重点，也是学生感觉掌握起来比较头疼的地方。下面选取近几年各省市的高考试题进行归纳分析，使考生通过典型实例，把握高考对before所引导的句型的命题规律，帮助同学们更好地解答此类题目。 1. before作为连词时的基本意义是“在??之前”，用于表示时间或顺序。

You can’t borrow books from the school library ______ you get your student card. (2009上海，32) A. before B. if C. while D. as

2. 表示“过了多久才??”，说明主句的持续时间比较长而从句的动作缓缓来迟。 (1) The American Civil War lasted four years _______ the North won in the end. (2005广东，30) A. after B. before C. when D. then

(2) Several weeks had gone by I realized the painting was missing. (2004宁夏，39) A. as B. before C. since D. when

3. 表示从句动作还没来得及发生或完成，主句动作就已经发生或完成了，意为“尚未??就”，“没来得及??就”，常用于before sb. can/ could…。

—Why didn’t you tell him about the meeting? ( 2006四川，35) — He rushed out of the room _________ I could say a word. A. before B. until C. when D. after

4. 表示“以免，以防，趁??还没有??”，强调动作的必要性，以避免或防止从句动作的发生。 He made a mistake, but then he corrected the situation _____ it got worse.（2003北京） A. until B. when C. before D. as

5. 用于 “It will be/would be＋一段时间＋before…”句型中，表示“还要过多长时间才??”；用于“It was＋一段时间＋before…”句型中，表示“过了多长时间才??”，强调时间的“长”。

(1) I’m sorry you’ve been waiting so long, but it’ll still be some time ____ Brian get back. (2008北京，34) A. before B. since C. till D. after

(2)The field research will take Joan and Paul about five months; it will be a long

time _____ we meet them again. （2007安徽，21）

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

(3) He was told that it would be at least three more months ______he could recover and return to work. （2007

江西，29）

A .when B. before C. since D. that (4) It was some time ___________we realized the truth. （2005山东） A. when B. until C. since D. before

6. 用于句型“It won’t be/was not＋一段时间＋before…”中，意为“不久就??”，“没过多长时间就??”，强调时间的“短”。

John thinks it won’t be long he is ready for his new job. (2010陕西，20) A. when B. after C. before D. since

7. when和hardly连用，表示“刚一??就??”。该结构主句常用过去完成时，当hardly位于句首时，要用倒装语序。

The girl had hardly rung the bell ______ the door was opened suddenly, and her friend rushed out to greet her. (2010福建，26)

A. before B. until C. as

D. since

8. before句型和其它相似句型的区别

有时候before引导的时间状语从句与since，when引导的时间状语从句在下列结构中较相似，容易混淆。 (1) “It be +时间段 + since引导的时间状语从句”表示“自从??已经有多长时间了”。主句用一般现在时或现在完成时。

It is almost five years we saw each other last time. （2005北京，春招） A. before B. since C. after D. when

(2) “It be +时间点 +when引导的时间状语从句”表示“某个动作发生时是某个时间”。主句谓语动词可以是一般过去时，也可以是一般将来时。

Because of the heavy traffic, it was already time for lunch break she got to her office. (2010四川，20)

A. since B. that C. when D. until 9. before long和long before的区别

(1) before long意为“不久，很快”（其中before是介词，long是名词），常在句中作状语，多与动词的过去时或将来时连用。例如：

·Before long, the news sped to every part of the world. 不久以后，这个消息遍布到了世界上的每一个地方。 ·I am so excited that I will enter a new school before long. 不久我就要进入一所新的学校学习，我感到非常兴奋。

（2）long before有两个用法：一为“老早，早就(单独使用，表示比过去某时早得多的时间)”。二表示“在??的很久以前，在还没有??的很久以前”。如：

·She had left long before his return/he returned 在他回来的很久以前她就走了。

·He had worked in the factory long before he got married. 在他还没有结婚的很久以前他就在这家工厂工作了。

注：此时的主句谓语通常用过去完成时，但有时也可用一般过去时(因为 before 已体现了动作的先后关系)。如：

·This happened long before you were born. 这事在你还没出生以前很久就发生了。 趁热打铁：

1. ——Tommy, your mum has been out without glasses ! ——Well, take it easy. she comes back home for them. A. It is long before that B. It won’t be long since C. It won’t be long before D. It will be long before

2. How long do you think the computer company brings out a new product ? A. it will be before B. will it be until C. will it be when D. it will be that

3. ——Have you any information about Julia? ——Pity! It’s a long time I met her last. A. before B. since C. until D. when

4. It' s quite a time _________ Yao Ming got injured, but it won' t be long he returns to the court.

A. since； before B. after; when C. before； since D. that; when 5. It may take a while _____ you find a hobby that truly interests yourself, so don’t give up. A. that B. before C. unless D. since 6. How long do you suppose it is ______he arrived there? A. when B. before C. after D. since.

（2）long before有两个用法：一为“老早，早就(单独使用，表示比过去某时早得多的时间)”。二表示“在??的很久以前，在还没有??的很久以前”。如：

·She had left long before his return/he returned 在他回来的很久以前她就走了。

·He had worked in the factory long before he got married. 在他还没有结婚的很久以前他就在这家工厂工作了。

注：此时的主句谓语通常用过去完成时，但有时也可用一般过去时(因为 before 已体现了动作的先后关系)。如：

·This happened long before you were born. 这事在你还没出生以前很久就发生了。 趁热打铁：

1. ——Tommy, your mum has been out without glasses ! ——Well, take it easy. she comes back home for them. A. It is long before that B. It won’t be long since C. It won’t be long before D. It will be long before

2. How long do you think the computer company brings out a new product ? A. it will be before B. will it be until C. will it be when D. it will be that

3. ——Have you any information about Julia? ——Pity! It’s a long time I met her last. A. before B. since C. until D. when

4. It' s quite a time __________ Yao Ming got injured, but it won' t be long he returns to the court.

A. since； before B. after; when C. before； since D. that; when 5. It may take a while _____ you find a hobby that truly interests yourself, so don’t give up. A. that B. before C. unless D. since 6. How long do you suppose it is ______he arrived there? A. when B. before C. after D. since.