Question

when和while用法上有什么区别?(过去进行时)

Answer 1

先弄清楚while和when的区别
when 当什么时 可表瞬间 事情可同时 或者先后发生
while 用于相伴发生的 同时进行的 持续性的

while 和 when在过去进行时中的用法：表示两个持续性的动作在过去同时发生用while，when后接一个短暂性的动作。持续性的动作用过去进行时,自然也就是要+ing了，短暂性的动作用一般过去时,所以不+ing.
所以是while后的动作+ing,when后的动作一般不+ing

1.I was doing my homework when someone knocked at the door.

2.We were walking along the river when suddenly it rained.

3.While he was waiting at the bus stop, the traffic accident happened.( While 后的分句必须用进行时)

4.While I was reading , my sister was sleeping.(表示对比,都用进行时)

Answer 2

很简单啊！when 后接的是过去式而 while 后接的是v-ing 形式，有的时候要根据句意使用，上课要好好听讲啊！

Answer 3

过去进行时+when+过去时
例：I was doing my homework when my father came back.
过去进行时+while+过去进行时
例：I was doing my homework while my mother was cooking meal.

Answer 4

When可接过去时和过去进行时，While只能接过去进行时

Answer 5

while 前后都用 -ing