-表示在过去某阶段或某一时刻正在发生

　　What were you doing at 8:30 last night? (过去某时刻正在发生)

　　-短暂性动词用过去进行时表示按计划、打算

　　During that time he was going with us.(表示打算)

　　-与always ,often ,usually 等连用表喜爱，讨厌等感情色彩。

　　He was always Changing his mind.

　　二、过去进行时与一般过去时的区别

　　A. 进行时表某一行为的“片断”一般时表示行为的“整体”和存在的状态。

　　I was reading the book at that time. (未读完，“读”的片段)

　　I read the book yesterday. (已读完，表整个“读”)

　　B、一般持续时间状语多与进行时连用

　　It was raining all night.(优先用was raining ,rained 为持续动词，故也可使用)

　　He was writing a letter the whole of afternoon. (短暂动词与持续时间连用，表反复，连续发生，不可用一般过去时)

　　C、while 时间状语从句中用短暂动词时只能用进行时。

　　例：He broke a chair while he was jumping up and down.

　　D、While 所在主从句动作大致持续相等时主从句一般都用进行时，但若是持续动词可都用一般过去时，两个动作一长一短时短的用一般时，长的用进行时。

　　I was cooking the dinner while he was playing the piano.(平行)

　　I cooked the dinner while he played the piano.

　　I saw him while I was walking to the station.

　　三、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。

　　I’m forgetting it . (=beginning to forget )

　　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.