as,when,while的区别当……的时候的区别

1.when所引导的时间状语从句,其中的谓语动词既可以延续的,又可以是非延续的.并且与主句中的谓语动词的发生没有先后顺序(无所谓发生在主句动词之前,同时或之后).
而while引导的时间状语从句，其中的谓语动词只能是延续性的,并且与主句中的谓语动词要同时发生.
例:
When he came,I was mending my bike.
不能说While he came,I was mending my bike.
(came是非延续性动词)
2.while引导的时间状语从句多用于进行时态(主句和从句都同时进行,一边...,一边...)，而when一般用法较普遍.
While he was doing his homework,his mother was cooking.
He was a great scientist when he was young.
3.as作“当……的时候”时引导短暂性动作的动词。
As he went into the room,the man stopped shouting.
（这句也可以用when)
当从句表示"随时间推移"连词只能用as，不能用when或while.
As the days went by,he became stronger.

when,while,as引导时间状语从句的区别 when,while,as显然都可以引导时间状语从句,但用法区别非常大.一、when可以和延续性动词连用,也可以和短暂性动词连用；而while和as只能和延续性动词连用.① Why do you want a n...