before句型辨析与解析

2022-08-03 12:08:12 文档大全网 [ 字体：小中大 ] [ 阅读： ]

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辨析,句型,解析,before
考点：before用法

一、句型“It + will be + 时间段 + before...”，表示“要过多久才…”，

“It + may be + 时间段 + before...”，表示“也许要过多久才……”。

其否定形式“It will/would not be +时间段+ before…”表示“过不了多久就……”。二、表示“在……之前就……”。主句与before从句中的两个动作按时间先后依次发生。三、表示“趁……”，“等到……”，或 “没等……就…… ”等。四、和其它相似句型的区别

“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 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。五、before long和long before的区别

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： The work will be finished before long. Before long he had to move on again.

long before意为“很久以前”（其中long是副词。long before单独使用时，before是介词；long before后接从句时，before是连词。）这个词组常与过去时或过去完成时连用，跟从句时也可用在一般现在时的句子中。例如： She said that she had heard of it long before. It will be long before he arrives. 【典型考例】

（1）The field research will take Joan and Paul about five months; it will be a long time _____ we meet them again.（2007安徽卷） A. after B. before C. since D. when

（2）—How long do you think it will be ______China sends a manned spaceship to the moon? （2006福建卷）

—Perhaps two or three years.

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

(3）It ________ long before we _____the result of the experiment.( 上海春招2002) A. will not be...will know B. is...will know C. will not be...know D. is...know

(4) Scientists say it may be five or six years_________ it is possible to test this medicine on human patients. （2004福建）

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

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

(6)The American Civil War lasted four years ___the North won in the end.(2005广东) A. after B. before C. when D. then (7) —Why didn't you tell him about the meeting? ( 2006四川卷) — He rushed out of the room _________ I could say a word. A. before B. until C. when D. after

(8) It was evening______ we reached the little town of Winchester. （2004天津）

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

(9) He made a mistake, but then he corrected the situation _____ it got worse.（2003北京） A. until B. when C. before D. as

(10） It is almost five years_____we saw each other last time. （2005北京春） A. before B. since C. after D. when

(11） — Did Jack come back early last night? （2005福建）

— Yes. It was not yet eight o’ clock________ he arrived hom

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

(12）You can’t borrow books from the school library_____you get your students card. (2009上海) A.before B.it C.while D.as

(13)I’m sorry you’ve been waiting so long, but it’ll be some time _____Brian gets back. (2008北京) A.before B.since C.till D.after