过去进行时常见标志词有：last night、last Saturday、this morning、the whole morning、all day、yesterday、from nine to ten last evening、at that time、last 、ago 、before等。例句如下：
1.I called you yesterday afternoon but there was no answer.
2.I was visiting a friend of mine most of the afternoon.
3.It was raining hard when I left my office.
4. When you called，I was eating.
5. When I was cleaning the windows， my brother was sweeping the floor.
6. Some students were playing football，while others were running round the track.
7. We were walking along the river when（suddenly） It rained.
8. They were watching TV when the lights went out.
9. She went to see Xiao Li. He was leaving early the next morning.