When she came in, I stopped eating.她进来时,我停止吃饭。(瞬时动词)
When I lived in the countryside, I used to carry some water for him.当我住在农村时,我常常为他担水。(延续性的动词)
We were about to leave when he came in.我们就要离开,就在那时他进来了。
2、While引导的从句的谓语动作必须是延续性的,并强调主句和从句的动作同时发生(或者相对应)。并且while有时还可以表示对比。例如:While my wife was reading the newspaper, I was watching TV. (was reading是延续性的动词,was reading和was watching同时发生)I like playing football while you like playing basketball.我喜欢踢 足球 ,而你喜欢打 篮球 。(对比)
3、As表示“一边……一边”,as引导的动作是延续性的动作,一般用于主句和从句动作同时发生;as也可以强调“一先一后。例如:We always sing as we walk.我们总是边走边唱。(as表示”一边……一边“)As we was going out, it began to snow.当我们出门时,开始下雪了。(as强调句中两个动作紧接着先后发生,而不强调开始下雪的特定时间)
4、由before和after引导的时间状语从句,表示两个动作一前一后发生。 例如:It will be four days before they come back. 他们要过四天才能回来。
After you think it over, please let me know what you decide.你仔细考虑过以后,告诉我你是怎样决定的。