一、过去进行时的概念 表示过去某一时刻正在进行的动作或过去某一阶段一直进行的动作。 例：I was doing my homework at 9:00 pm last night. 二、过去进行时的构成： （1）肯定句：主语+was/were+现在分词+其他 例：He was working when I came in. （2）否定句：主语+was/were+not+现在分词+其他 例：There weren't working when we arrived. （3）疑问句...
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