过去进行时
[玫瑰]过去进行时 when 一般过去式
例如：I was telephoning a friend when Bob came in.
[玫瑰]一般过去式 while 过去进行时
例如：She didn’t want to stay in bed while the others were working in the fields.
He broke a chair while he was jumping up and down.
[玫瑰]while 所在主从句动作持续相等时间时，主从句都用进行时；两个动作一长一短，则短的用一般过去时，长的用过去进行时。
例如：I was cooking the dinner while he was playing the piano.
He called his mother every week even while he was traveling around the world.
过去完成时
[玫瑰]表示某个动作在“过去的过去”完成。
例如：The bus had already left by the time I got there.
例如：By the end of last week, she had stayed in the west of China for two months helping the homeless children.
[玫瑰]在含有间接引语的宾语从句中，主句一般过去时，从句过去完成时。
例如：He told me that he had already seen the film.
过去将来时（would do；was/were going to do）
[玫瑰]come，go，start等动词，其过去进行时表示过去按计划即将发生的动作。
例如：He said he was coming this evening.
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