高三課本第十五單元，INTER GATING SKILLS 和 WORKBOOK READING部分有如下的句子：
⒈The shop was successful，but it was about sixty years before people started to buy jeans for fashion as well as for work.
⒉However，it probably will not be long before the other mountainous areas of China such as Sichuan，Xinjiang and Yunnan are developed，and as more facilities become available，prices will almost certainly fall.
其中涉及到before的用法，下面就其用法進行總結。
一、可以用作介詞
⒈)指時間上早於，在……之前，如：
She has lived here since before the war.
她從戰前就一直在這兒住。
⒉)指位置在前面，如：
We knelt down before Grandma's grave.
我們在奶奶的墓前跪下。
⒊)指順序或排列在之前，如：
Your name comes before mine on the list.
名單上你的名字在我之前。
⒋)在某人面前，如：
She said it before the witness.
他是當著證人的面說的。
二、作為連詞
其基本含義是「在……之前」，又可以根據不同語境靈活翻譯成「才」、「還沒來得及就……」、「趁……」、「就」等。具體用法如下：
⒈)與情態動詞can/could連用
這時候從句雖為肯定形式，根據漢語表達習慣譯成「還沒來得及就」，如：
Before I could get in a word，he had measured me.
我還沒來得及插話他就為我量好了尺寸。
Before she could move，she heard a loud noise，which grew to a terribl eroar.
她還沒來得及邁步，就聽見一聲巨響，接著就是可怕的隆隆轟鳴。
⒉)用於肯定句中強調主句所表達的時間，距離長，或花費的精力大，譯成「才」
We had sailed four days and four nights before we saw lands.
我們航行了四天四夜才看到陸地。
We waited a long time before the train arrived.
我們等了很長時間火車才到。
⒊)用於否定句中，強調主句所表達的時間，距離短，或花費的精力小，譯成「不到……就」如：
We hadn't run a mile before he felt tired.
我們跑了還不到一英裡他就累了。
⒋)主句含有hardly，scarcely等半否定副詞時可以譯為「剛……就」
這時候主句應用過去完成時態，從句用過去時，還可以用when替代before如：
We had scarcely reached the school before/when the bell rang.
我們剛到學校鈴聲就響了。
⒌)有時還有「寧願」的意思
I'd shoot myself before I apologized to him.我寧死也不向他道歉。
⒍)用於It+be/take+時間段+before句型
在這一句型中又可以根據主從句的時態分成兩種情況。
若主句是一般時將來時態，從句是一般現在時.若主句是肯定句意思是「要過多長時間才」;若主句是否定形式翻譯成「用不了多久就」。
It will be two weeks before everything returns to normal.
兩周之後一切才能恢復正常。
It will be many years before the situation improves.
這種狀況或許要過許多年才能得以改善。
It won't be long before we meet again.用不了多久我們就會再見面的。
這時若主句是一般過去時從句也是一般過去時。若主句是肯定句翻譯成「多長時間之後才」，若主句是否定形式翻譯成「沒過多久就」。如：
It was some time before I realized the truth.
過了很長一段時間我才了解到真相。
It wasn't long before she became a brave solider.
沒過多久她就成了一名勇敢的戰士。
After that it still took seven years before they got married.
他們又過了七年才結婚。
注意：當主句的謂語動詞為延續性動詞時，before與until有時可以互換。It was an hour before/until the police arrived.
■鞏固練習
⒈(2004天津)It was evening ________ we reached the little town of Winchester.
Athat B.until C.since D.before
2.(2004全國)Several weeks had gone by ________ realized the painting was missing.
A.as B.before C.since D.when
3.(2005廣東)The America Civil War lasted four years ______ the North won in the end.
A.after B.before C.when D.then
4.(2005山東)It was some time _______ we realized the truth.
A.when B.until C.since D.before
5.(2006四川)-Why didn't you tell him about the meeting?
-He rushed out of the classroom _______ I could say a word.
A.before B.until C.when D.after
6.(2006福建)-How long do you think it will be __ china sends a manned spaceship to the moon?
-Perhaps two or three years.
Awhen B.until C.that D.before
參考答案：DBBDAD
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