从句中when和while有什么区别

从句中when和while有什么区别

When,while,as,before,after
When means at the time that or during the time that解释为当.时或在.期间
While means during the time that解释为在.期间,还可解释为可是反而=whereas
As means at the same time that解释为同时,一边.一边.
两个习惯动作同时when=whenever=if=every time 句中时态用未进行（一般）时态
She felt ill when(ever) she ate oyster.=If she ate oyster she felt ill.
两个延续动作同时(when)=while句中时态可用未进行（一般）时态也可用进行时态
I was cooking the dinner while(when) he was playing the piano.
I cooked the dinner (when) while he played the piano.
两个延续动作延续时间恰好同等可用as long as
He worked as long as we played.
两个瞬间动词同时when=as soon as=the instant=immediately=the moment=just as
=directly=hardly/scarcely…when=no sooner than来强调两个瞬间动作同时发生
The dog barked when it heard a noise.
I knew he wasn’t an Englishman the moment he began to speak English.
Tell me immediately you have any news.
I had hardly left when the quarrel started.=Hardly had I left when the quarrel started.
瞬间动作在延续动作过程中发生when=while=as
I met Marry as(while) I was going home.As(when) we were talking,the rain began.
两个动作逐步发展或逐渐变化只能用as
As you get older you get more optimistic.You will know it as you grow.
总之,强调点时间用when,强调段时间用while,强调同时或逐渐变化用as.
When还可以表示先后=before=after.
He finished his homework before he went to bed.
=He went to bed after he finished his homework..
=He had finished his homework when he went to bed.
另外,while还有对比的意思.
he is lasy while she works hard.