过去进行时的基本概念
过去进行时(past continuous tense)表示过去某一时刻或某段时间正在进行的动作。如：
I was practicing the violin at eight o'clock yesterday evening. 昨晚八点钟我正在练习小提琴。
When Walter arrived home，his sister was doing her homework.沃尔特到家时，他妹妹正在做作业。
Pat was watching TV all evening. 帕特整个晚上都在看电视。
过去进行时的形式
过去进行时由was(第一、三人称单数)或were (其余各人称和数)加现在分词所构成。
过去进行时的基本用法
表示在过去某一时刻或某一段时间正在进行的动作，这一特定的时间往往须用时间状语来表示。如：
She was reading an English magazine when I came in.我进来时她在看一本英文杂志。
It was getting dark.天黑了。
They were working all day yesterday.他们昨天整天工作。
We were cleaning the auditorium from 7 to 9 last night.昨晚七点到九点我们在打扫大礼堂。
I met him when he was crossing the street.他过街时我碰见他。
过去进行时的其他用法
1)表示移动的动词go，come，start，stay，leave等的过去进行时，可以表示过去将来发生的动作。如：
They wanted to know when we were leaving for Shanghai. 他们想知道我们什么时候到上海去。
She asked whether he was starting then ext day.她问他是否第二天就动身。
2)动词go的过去进行时态加动词不定式，可以表示在过去某一时间之后将要发生的动作。(比较8.24的3)如：
They said they were going to set up a nursery.他们说他们要设立一个托儿所。
She said the foreign guests were going to visit the Shanghai in dustrial Exhibition.她说外宾要去参观上海工业展览会。
The monitor announced that our new teacher was going to speak to us.班长宣布新老师要跟我们讲话。
3)过去进行时可用来描写故事发生的背景。如：
It was a dark night. The wind was blowing hard and the rain was falling heavily. A young woman suddenly appeared on the riverbank. it was Xier. She had just escaped from Huang Shiren's house.那是一个漆黑的夜晚。风刮得很厉害，雨下得很大。一个年轻妇女突然出现在河岸上。这就是喜儿。她刚从黄世仁的家里逃了出来。