1. 过去进行时的定义
过去进行时主要表示过去某一时刻正在进行的动作，或表示过去某一阶段一直在进行的动作。如：
I was having a talk with Li Hua at that time. 那时，我正在跟李华谈话。
I was watching TV at home last night. 昨晚我一直在看电视。
2. 过去进行时的结构及句型变化
过去进行时由“was / were + 现在分词”构成。如：
I was doing my lessons then. 那时，我在做功课。
We were cleaning the house. 我们在打扫房子。
过去将来时态的肯定句、否定句和疑问句形式：
肯定句例句：I was walking down the street when a UFO landed.
否定句例句：I wasn't walking down the street when a UFO landed.
一般疑问句例句：Were you walking down the street when a UFO landed?
特殊疑问句例句：What were you doing when a UFO landed?
3过去进行时的用法详解
(1)表示在过去某一时间正在进行的动作，此时句中往往有表示过去的时间状语then,
at that time, this time, yesterday等。
I was doing my homework when my mother came to home.
(2)叙述在过去的同一时间都在进行的几个动作，通常用While
I was studying at college while my brother was teaching at university..
(3)表示在过去某一段时间内一直持续进行的动作
They were expecting you yesterday, but you didn’t turn up.
4. 使用过去进行时应注意的几点
(1) 过去进行时可表示按计划、安排过去某时刻将要发生的动作。如：
He said they were leaving for Beijing this afternoon. 他说他今天下午要去北京。
(2) 动词hope, wonder等的过去进行时常用来表示提出要求，虽然表示现在的内容，但语气比一般现在时或一般过去时要委婉。如：
I was wondering whether you could come to join us. 我想你能否过来跟我们一起活动?
(3) 过去进行时中有always, forever, continually, constantly修饰时，表示说话人的赞赏或厌烦的感情。如：
He was always thinking of others. 他总是想到人家。
4. 过去进行时与一般过去时的区别
(1) 过去进行时强调动作在过去某时刻正在进行或持续，而一般过去时表示动作的完成。如：He was writing his composition last night. 他昨晚在写作文。(不一定写完) He wrote his composition last night. 他昨晚写了一篇作文。(已经写完)
(2) 表示过去的状态、感觉及心理活动的静态动词(如be, like, love, hate, fear, own, hear, see, know, want, notice)可用于一般过去时，但通常不用于进行时。如：
I hated it when a man spoke with his mouth full of food. 我讨厌人们说话时口里含着食物。
(3) 一般过去时与always, constantly, forever, continually等连用，表示“过去经常性、习惯性的动作”;而过去进行时与always, constantly, forever, continually等连用，表示动作的重复，常带有感****彩。如：
He always got up at six. 他过去总是六点起床。
He was always thinking of his work. 他总是一心想到工作。
(4) 有时过去进行时可以用来替换一般过去时，但一般过去时表示主语的行为是经过认
真考虑的;而过去进行时表示一种较随便或没有进行仔细考虑的行为。如：
I thought that he would agree with us. 我原以为它会同意我们的。
I was thinking of persuading him to follow my advice. 我想到了要说服他接受我们的建议。
5.英语中有四类动词一般不用进行时（不用现在进行时和过去进行时）
1)表心理状态、情感的动词，如love ,hate ,like ,care ,respect ,please ,prefer ,know 等，若用进行时则词意改变。
2)表存在、状态的动词，如appear ,exist ,lie ,remain ,stand ,seem等
3)表感觉的动词，如see ,hear ,feel ,smell ,sound ,taste等.
4)表一时性的动词，如accept ,allow ,admit ,decide ,end ,refuse ,permit ,promise等。
