一、過去進行時除了可以表示過去某段時間發(fā)生的事情外，也可以表示在過去某個時間點發(fā)生的事情，時間點可以用介詞短語、副詞或從句來表示。例如：
1. What was she doing at nine o'clock yesterday？
昨天晚上九點她在做什么？（介詞短語表示時間點）
2.Tom was getting up at six o’clock every day that week.
湯姆那一周里每天都是六點鐘起床。
3.I was washing my clothes at this time yesterday．
昨天的這個時候，我正在洗衣服。
4.They were playing games at 5：00 p.m. yesterday．
昨天下午五點他們正在玩游戲。
5. What were you doing in the classroom yesterday afternoon?
昨天下午你在教室里干什么?
6. When I saw him he was decorating his room.
當我看見他的時候他正在裝飾房間。（when從句表示時間點）

二、在復(fù)合句中，如果主要動作和背景動作都是延續(xù)的或同時發(fā)生的，那么主從句的動詞都可用過去進行時。例如：
1. While he was waiting for the bus，he was reading a newspaper.
他邊等車邊看報。（兩個動作都是延續(xù)的）
2.He was cleaning his car while I was cooking.
他擦車時我在做飯。（兩個動作同時進行）
3.They were singing while we were dancing.
我們跳舞的時候他們正在唱歌。
4.When I was doing my homework,my mother was cooking.
當我正在做功課的時候，我媽媽正在做飯。
5.When my mother was doing the housework,my father was watching TV.
當我媽媽正在做家務(wù)的時候，我爸爸正在看電視。