首先要明确,while 表“当...时候”的时候,主句和从句的两个谓语动词最好都使用进行时态,而when则有多种用法
1.Sb.was doing ...when sb.did ...
2.sb.did ...when sb.was doing ...
3.sb.was doing ...when sb.was doing ...
换句话说,when的使用范畴比while更广一些
1.was taking,when,rang
电话铃响的时候她正在洗澡.
2.started; when; was walking
当我走路上学时,天开始下雨.
3.When; arrived; were waiting
当他刚才到达机场时,他的朋友正在等他.
4.were eating; when; knocked
当某人敲门时,他们正在吃饭.
5.met; when; was walking
当我在街上走路时,我碰到一个老朋友.(and需改成an)
6.caught; when; were working
当他们昨天在工作时,电视机着火了.
需要答案解释的话请补充说明