职称英语语法知识点:时间状语从句

时间:2017-07-29 职称英语 我要投稿

  导语:时间状语从句(adverbial clause of time),语法句式,是用表示时间的连词连接一个句子作状语,这样的主从复合句就是时间状语从句。下面小编为您收集整理了职称英语中时间状语从句的用法,希望对您有帮助!

  (1)as、when、while

  as表示“当……的时候”,往往和when/while通用,但它着重强调主句与从句的动作或事情同时或几乎同时发生。

  She came up as I was cooking.(同时)

  The runners started as the gun went off.(几乎同时)

  when:(at or during the time that)既可以表示在某一点的时候,又可表示在某一段时间内,主句与从句的动作或事情可以同时发生也可以先后发生。

  It was raining when we arrived.(指时间点)

  When we were at school, we went to the library every day.(在一段时间内)

  while意思是“当……的时候”或“在某一段时间里”。主句中的动作或事情在从句中的动作或事情的进展过程中发生,从句中的动词一般要用延续性动词。在when表示a period of time时,两者可以互换。

  Please don't talk so loud while others are working.

  He fell asleep while/when reading. Strike while the iron is hot.(用as或when不可,这里的while意思是“趁……”)

  (2)引导时间状语从句的连接词除上述外还有:

  ①till、not…until…、until、before、since

  Don't get off the bus until it has stopped.

  He waited for his father until(till)it was twelve o'clock.

  It will be five years before he returns from England.