We were watching TV from seven to nine last night.
昨天晚上七点到九点的时候我们在看电视。
What was he researching all day last Sunday?
上周日他一整天都在研究什么？
My brother fell while he was riding his bicycle and hurt himself.
我哥哥骑自行车的时候从车上摔下来，受伤了。
It was raining when they left the station.
他们离开车站的时候天正在下雨。
When I got to the top of the mountain, the sun was shining.
当我到达山顶的时候，阳光灿烂。
What was she doing at nine o'clock yesterday??
昨天晚上九点她在做什么？ (介词短语表示时间点)
When I saw him he was decorating his room.
当我看见他的时候他正在装饰房间。 (when从句表示时间点)
While he was waiting for the bus, he was reading a newspaper.
他边等车边看报。 (两个动作都是延续的)
He was cleaning his car while I was cooking.
What were you doing at 8:30 last night? (过去某时刻正在发生) He was always changing his mind During that time he was going with us.(表示打算) He was always changing his mind. I saw him while I was walking to the station.
温馨提示：答案为网友推荐，仅供参考