有些詞只要出現(xiàn)句子中，就表示這個句子是過去時，常見的標志性詞語有：yesterday , last , ago , before , in+年或月 , on+日 , just now(或者a moment ago) ；再加上was+v-ing，就可以判斷這個句子是過去進行時了。例如：
1.I called you yesterday afternoon but there was no answer.
昨天下午我打電話給你，但是沒有人接電話。
2.I was visiting a friend of mine most of the afternoon.
我昨天下午大部分時間，都在一個朋友家里。
3.It was raining hard when I left my office.
當我離開辦公室時，雨下得正大。
4. When you called，I was eating.
你打電話時，我正在吃飯。
5. When I was cleaning the windows， my brother was sweeping the floor.
我在擦窗戶的時候，我弟弟在拖地。
6. Some students were playing football，while others were running round the track.
一些學生在踢足球，同時別的學生正在跑道上跑步。
7. We were walking along the river when（suddenly） It rained.
我們沿著河邊散步，突然下起雨來。
8. They were watching TV when the lights went out.
停電時，他們剛好在看電視
9. She went to see Xiao Li. He was leaving early the next morning.
她去看小李。他第二天一早就要離開此地了。
10. She asked him whether he was coming back to lunch.
她問他晚飯是否準備回來吃。