I / he/ she/ it was working
we/ you/ they were working
At that time she was working in Oxford. 那時，她正在牛津大學工作。
It was raining at 6 o'clock this morning. 今天早晨六點鐘天正下著雨。
What were you doing when I phoned you last night? 昨晚我給你打電話時你在幹什麼？
at 8 o'clock yesterday morning昨天早上8點，
at this time last year去年的這個時候，
...when I phoned you yesterday昨天我打電話給你的那個時候，
...while we were having the meeting我們在開會的時候。
They were watching TV when I entered the room. 我進入房間時，他們正在看電視。
The children were playing with their toys while I was eating my dinner.
He was studying in Cambridge between 1999 and 2001. 在1999年和2001年那段時間，他在劍橋學習。
From January to March I was traveling in Egypt. 從3月份到4月份期間，我在埃及旅遊。
He worked from morning till night yesterday.
It was a sunny morning. Some people were sitting on the riverbank. Some were walking with
their dogs. Several boys were playing football nearby...
He telephoned me, saying that his aunt was coming to see me soon.
這類動詞有 come來, go去, leave離開, start開始, stay逗留 等。主語必須是人。
We built a bridge last winter. 去年冬天我們修了一座橋。
We were building a bridge last winter. 去年冬天我們在修一座橋。