Before作为连词的用法

 It took nearly two hundred years before I was built as an analytical machine by Charles Babbage. 

       Before作为连词的用法

        其基本含义是“在……之前”，又可以根据不同语境灵活翻译成“才”、“还没来得及就……”、“趁……”、“就”等。具体用法如下：

1) 用于It+be/take+时间段+before句型

        在这一句型中又可以根据主从句的时态分成两种情况。

      A) 若主句是一般将来时态，从句是一般现在时。

•  若主句是肯定句意思是“要过多长时间才”；  
•  若主句是否定形式翻译成“用不了多久就”。

    It will be two weeks before everything returns to normal.    两周之后一切才能恢复正常。

    It will be many years before the situation improves.  这种状况或许要过许多年才能得以改善。

    It won't be long before we meet again.用不了多久我们就会再见面的。

     B)  这时若主句是一般过去时从句也是一般过去时。

• 若主句是肯定句翻译成“多长时间之后才”，
• 若主句是否定形式翻译成“没过多久就”。如：

    It was some time before I realized the truth. 过了很长一段时间我才了解到真相。

    It wasn't long before she became a brave solider. 没过多久她就成了一名勇敢的战士。

    After that it still took seven years before they got married. 他们又过了七年才结婚。

   It took nearly two hundred years before I was built as an analytical machine by Charles Babbage. 差不多过了200年后，查尔斯.巴比奇才把我制成了一台分析机。

       注意：当主句的谓语动词为延续性动词时，before与until有时可以互换。

    It was an hour before/until the police arrived.

    2)before与情态动词can/could连用

        这时候从句虽为肯定形式，根据汉语表达习惯译成“还没来得及就”，如：

    Before I could get in a word，he had measured me. 我还没来得及插话他就为我量好了尺寸。

    Before she could move，she heard a loud noise，which grew to a terrible roar.  她还没来得及迈步，就听见一声巨响，接着就是可怕的隆隆轰鸣。

    3)before 用于肯定句中强调主句所表达的时间，距离长，或花费的精力大，译成“才”

      They   21    (struggle) for about four hours before they could pull the babies out with ropes and a vehicle.我们营救了四个小时最后才用绳子和起吊设备把两头小象拉出来了。

    We had sailed four days and four nights before we saw lands.  我们航行了四天四夜才看到陆地。

    We waited a long time before the train arrived. 我们等了很长时间火车才到。

    4)用于否定句中，强调主句所表达的时间，距离短，或花费的精力小，译成“不到……就”如：

    We hadn't run a mile before he felt tired.  我们跑了还不到一英里他就累了。

    5)主句含有hardly，scarcely等半否定副词时可以译为“刚……就”

        这时候主句应用过去完成时态，从句用过去时，还可以用when替代before如：

     We had scarcely reached the school before/when the bell rang. 我们刚到学校铃声就响了。

    He had scarcely escaped when he was recaptured.他刚逃掉就被逮住了。

  He had hardly arrived when she started complaining.他刚一到, 她就开始抱怨起来。

    6）用在含有before的主从复合句中
        用在含有before的主从复合句中，一般在从句中使用一般过去时，主句中使用过去完成时。例如：
     Lily had written some letters before she went out shopping.
       有时，也可以在从句中用过去完成时，主句中用一般过去时，这样就可使描述更为生动。试比较：
     We got to the station before the train had left. 火车尚未开动之前，我们就到了车站。
     We had got to the station before the train left. 火车开出之前，我们就已经到了车站。
      像after一样， before本身就能明确地表示时间的先后关系，故多数主从句均使用一般过去时，而无需使用过去完成时。例如：
  Many people left for home before the film ended.电影尚未放完，许多人就起身回家了。

      连接：

by， before， when， until, after 在过去完成时态中应用 

    7) before有时还有“宁愿”的意思

    I'd shoot myself before I apologized to him.我宁死也不向他道歉。

 ⒈ It was evening ________ we reached the little town of Winchester.

    Athat B.until C.since D.before

 2. Several weeks had gone by __ we realized the painting was missing.

    A.as   B.before  C.since  D.when

    3. The America Civil War lasted four years ______ the North won in the end.

    A.after B.before C.when D.then

    4. It was some time ___ we realized the truth.

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

    5. 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. 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

    参考答案：DBB

                        DAD