when、while、assoonas、until的用法及区别

Question

when、while、as soon as、until的用法及区别

Answer 1

when引导的从句的谓语动词可以是延续性的动词,又可以是瞬时动词.并且when有时表示“就在那时”.
例如：
When she came in,I stopped eating.她进来时,我在吃饭.(瞬时动词)
When I lived in the countryside,I used to carry some water for him.当的住在农村时,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.
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）
as soon as
as soon as 意义为“一…就” ,引导时间状语从句,可置于句首或句末,最常见的用法是在将来时态的情境中,遵守“主将从现”,的原则,i.e.
1.I'll write you as soon as I get there.
我一到那儿,就给你写信.
2.They will post the tickets to me as soon as they receive my cheque.
他们收到我的支票后就立刻把票寄给我.
3.Let us start as soon as he comes.
等他一来我们就动身.
当然也有用在过去时态的情境中,i.e.
I arranged the flowers in the vase as soon as I came back home.
一回到家里,我就把花在花瓶里插好.
As soon as his father went out,the boy ran to the cinema.
爸爸刚出门,那男孩就跑向电影院.
until在肯定句中,可以和时间状语连用,表示“(动作或状态的继续)一直……为止”.例如:I waited until nine o’clock,andthen I left.我一直等到9点才离开.2.用在否定句中,表示“到……为止”“直到……才”,常与表示瞬间动作的动词连用.