Period Three　Grammar & Writing

　　时间状语从句

　　在复合句中起时间状语作用的句子称为时间状语从句。

　　1．时间状语从句常由下列连词引导：when(当......时候)，whenever(任何时候)，as(随着)，while(在......期间)，before(在......以前)，after(在......之后)，since(自从)，as soon as(一......就)，until(直到)，once(一旦)等。如：

　　When we lived in town，we often went to the theatre.

　　我们住在城里时常去剧院看戏。

　　Before they reached the station，the train had gone.

　　他们到达车站前，火车就已经开走了。

　　I have written home four times since I came here.

　　自从到这儿来后我往家里写了四封信。

　　As years go by，China is getting stronger and richer.

　　随着时间一年一年过去，中国变得越来越富强了。

　　We all insist that we should not rest until we finish the work.

　　我们都坚决要求不完工不休息。

　　注意：(1)when在be about to do...when...，be doing...when...，had(just)done...when...，be on the point of doing...when...等结构中，作"在那时"讲，表示某件事正要发生、正在发生或刚刚发生，另一动作同时发生。

　　He was about to leave when someone knocked at the door.

　　他刚要走就有人敲门。

　　I was thinking of this when I heard my name called.

　　我正想着这件事时，突然听到有人叫我的名字。

　　(2)时间状语从句中用一般现在时表示将来的动作。如：

You will get to know when you grow up.