过去进行时（Past continuous tense或Past Progressive tense）表示在过去某一时刻或某一段时间内发生或进行的动作或状态.
过去进行时（Past continuous tense或Past Progressive tense）表示过去某时某刻正在进行的动作（不强调是否完成）.（过去进行时具体用在什么地方,看下面的内容）
具体概念
一、 概念和用法：过去进行时
  表示在过去某一时刻或某一段时间内进行或发生的动作.其形式为was /were + V-ing.常与表示过去的时间状语连用,如：last night,last Saturday等；或者与when,while,as引导的过去时间状语连用.
  如：We were watching TV from seven to nine last night. 昨天晚上七点到九点的时候我们在看电视.
        What was he researching all day last Sunday? 上周日他一整天都在研究什么?
二、 过去进行时可以表示在过去某个时间点发生的事情.时间点可以用介词短语、副词或从句来表示.
  如：What was she doing at nine o‘clock yesterday? 昨天晚上九点她在做什么? （介词短语表示时间点） 
        When I saw him he was decorating his room. 当我看见他的时候他正在装饰房间.（when从句表示时间点）
三、 在复合句中,如果主要动作和背景动作都是延续的或同时发生的,那么主从句的动词都可用过去进行时.
  如：While he was waiting for the bus,he was reading a newspaper.他边等车边看报.（两个动作都是延续的） 
        He was cleaning his car while I was cooking. 他擦车时我在做饭.（两个动作同时进行）
四、 通常不能用于过去进行时的动词主要有：agree,is,am,are,believe,belong,care,forget,hate,have（有）,hear,know,like,love,mean,mind,notice,own,remember,seem,suppose,understand,want,wish等.
    如：误：I was knowing the answer.
          正：I knew the answer. 我知道答案.
          误：I wasn‘t understanding him.
          正：I didn‘t understand him. 我不明白他的意思.
结构组成编辑
1. 过去进行时由“主语+was/were + 动词ing”构成
   如： We were having supper when the phone rang. 我们正在吃晚饭时电话响了.
2. 过去进行时的否定式由“主语+was/were not +现在分词”构成
   如： This time yesterday Jack was not watching TV. He was repairing his bike. 昨天这个时候,杰克不是在看电视,而是在修理自行车.
3. 过去进行时的疑问式由“was/were +主语+ 现在分词”组成
   如： Were you playing basketball at four yesterday afternoon? 昨天下午四点你们在打篮球吗?
句型
肯定句：主语+was/were+doing+其它
否定句：主语+was/were+not+doing+其它
一般疑问句：问语=Was/Were+主语+doing+其它
答语：Yes,I was/were.或No,I wasn't/weren’t.
特殊疑问句：特殊疑问词+一般疑问句+其它
例句
1、We were having supper when the phone rang. 我们正在吃晚饭时,电话响了｡
2、This time yesterday Jack was not watching TV. 昨天这个时候杰克不在看电视.
3、He was repairing his bike.他在修理自行车.
4、When/While we were having supper, the light went out. 我们正在吃饭时,灯熄灭了.
5、While we were talking, the teacher came in. 当我们正在谈话时,老师进来了.
6、While he was waiting for the bus, he was reading a newspaper.他边等车边看报.
7、He was cleaning his car while I was cooking. 他擦车时,我正在做饭.
8、Tom was getting up at six o’clock every day that week. 汤姆那一周里每天都是六点钟起床.