高校问答不丹 中国 边境:过去进行时中when，while前后的时态
来源：百度文库 编辑：高校问答 时间：2024/04/27 18:38:20
求救，还有三天期中考试了
前后的时态要看具体的问题．
一般表示过去某个时间正在进行的动作，如：
what were you doing when he came in.
doing是一个持续性的动作，所以用过去进行时，而came是短暂性的动作，用一般过去时．when 长用于表示短暂性的动作．而while则多是说明持续性的动作．what wreyou doing while he wasdoing his homework.
i was doing my homework when my mother came home yesterday.
i was doing my homework while my father was busy working in his office last night.
when和 while 都可以引导时间状语从句， 表示一个动作发生另一个动作正在进行，如： when his mother came home, he was doing his homework.
while he was waiting for the bus he read a book.
when he was sleeping his father cam eback.
前后的时态要按实际情况来确定。