第1个回答 2010-01-30
When：以when引导的时间状语从句，其主句表示某些动作正在进行时用过去进行时态。
e.g.They were watching TV when I got to their house.
当我到他们家的时候，他们正在看电视。
While：while引导的时间状语从句常常用过去进行时态。
e.g.While he was sleeping ,I was doing my homework.
当他在睡觉的时候，我正在做作业。
其实记这个最简单的方法就是看到when就想到一个用过去式一个用过去进行时，
看到while就想到两个都用过去进行时。
不过用过去进行时的时候要想到要用延续性的动词。本回答被网友采纳
第2个回答 2010-01-30
我给你的这些初中绝对够用～～
1.与WHILE比较,WHEN用得较广,所引导的从句中动词既可是延续性的,又可是非延续性的,WHILE动词只能是延续性的
如:When the fire broke down,all the sthdents were sleeping.
当火灾发生时，所有的学生正在睡觉．
The telephone rang while I was taking a bath.
我在洗澡时，电话响了．
2.当两个表示时间延续的动作同时发生而又具有对比意味时，用WHILE，这样的复合句中，主从句时态相同
如：Father was preparing a report while I was playing PC games.
爸爸正在准备一份报告，我在玩计算机游戏．
While I played the harp,my sister did her homework.
我在弹竖琴，姐姐在做功课．
3.表述两个发展变化中的情况时常用AS
如：As he talked on,he got more and more excited.
他越说越激动．
As you grow older,you'll know better about youself.
随着年龄的增长，你就会越来越了解自己．
4.表示”一边……一边……“时用AS
如：As he was reading,he was shaking his head,which surely slowed down his reading speed.
他边读书边摇着头，这当然降低了他的阅读速度．
They talked as they walked along the river.
他们边沿河走边谈．
5.表示随着短暂动作的发生，另一行为伴随着发生用AS．
如：My cap was blown away as I sat down.
我坐下时帽子被风吹走了．
6.在时间状语中，用一般现在时表示一般将来时，用一般过去时表示过去将来时．
如：When you get there,ring me up.
你到后，给我来个电话．
Don't forget to bring your camera here when you come.
当你来时别忘了带相机．