我们学过了现在进行时及其用法后，就不难理解过去进行时（The Pass Progressive）。
过去进行时主要表示过去某个时刻正在进行的动作，由 be 动词的过去式（were /was）加现在分词构成。
主语 + were / was + 现在分词
常和表示过去的时间状语如 then，at this（that）time，yesterday，last year 等连用。但值得注意的是，在很多情况下，句中并没有表示时间的状语，需要通过上下文来表示。
例如：What were you doing at about 4 o'clock yesterday afternoon?
I was listening to music.
Jane was doing her homework last night.
例如：Just as I was leaving the house，the telephone rang.
He broke his leg when he was playing football.
She was reading when he called.
例如：While you were writing letters，I was reading a book.
While we were having breakfast，John was talking on the telephone.
例如：She was leaving early the next morning.
她第二天一早就要离开。（此处的 was leaving 表示过去将来的动作，不是过去进行时。）
She asked whether he was coming back for lunch.
她问他是否回来吃午饭。（此处的 was coming 表示过去将来的动作，不是过去进行时。）
We were coming to see you，but it rained（so we didn't.）
（这种用法仅限少数瞬间动词，如 come，go, leave, arrive 等 ）
例如：My boss was wondering about it.
I was wondering how to get there quickly.
They were wondering where to spend the weekend.
（1）肯定句：主语 + were / was + 现在分词
例如：I was watching TV when you came to visit me last night.
We were playing basketball on the playground then.
（2）疑问句：Were / Was + 主语 + 现在分词 + ? (一般疑问句)
例如：Was he reading a book at 3 o'clock yesterday afternoon?
Yes, he was. 是的，他在读。
No, he was not. (he wasn't.) 不，他没在读。
Were they swimming in the river when the teacher came?
Yes, they were. 是的，他们在游泳。
No, they were not.(they weren't) 不，他们没在游泳。
特殊疑问句: 在一般疑问句前加 What, Where, Why, Which, How 等
What were you doing while your mother was cooking?
Where is she singing when you saw her?
Why were they all sleeping at about 10 o'clock this morning?
Which car was he driving at the race?
How were you describing the accident then?
（3）否定句：主语 + were not / was not + 现在分词
例如：The dog was not barkingwhile the stranger was passing by.
I wasn't doingmy homework when you knocked the door.
They said that they weren't makinga snowman.
他们说他们不去堆雪人了。（ 注意：weren't making 表示过去将来的动作）