关于英语的问题 when,while和as 都当“……的时候”的区别,最好有例句.

（1） while,when,as 这三个连词都可引导时间状语从句,但用法有所不同.
1) 当某事正在进行的时候,又发生了另一件事.While,when,as 都可用来引导表示“背景”的时间状语从句.例如：
As/When/While I was walking down the street I noticed a police car.
2) 当两个长动作同时进行的时候,最常用的是while.例如：
While mother was cooking lunch,I was doing my homework.
3) 当两个动作都表示发展变化的情况时,最常用的是as.例如：
As children get older,they become more and more interested in things around them.
4) 当两个短动作同时发生时,或表示“一边…一边…”时,最常用as.例如：
Just as he caught the fly,he gave a loud cry.She looked behind from time to time as she went
5) 当从句的动作先于主句的动作时,通常用when.例如：When he finished his work,he took a short rest.
6) 当从句是瞬间动作,主句是延续性动作时,通常用when.例如：When John arrived I was cooking lunch.