过去正在发生的动作
结构: 肯定句 主语+was/were+动词的现在分词+其他
eg: I was doing my homework at 8 o’clock yesterday evening.
否定句 主语+was/were not +动词的现在分词+其他
They were not staying at home at this moment last Sunday.
疑问句 Was/Were + 主语+ 动词的现在分词+其他
Were you sleeping when I called you last night?
关键词:具体时间如:at ten o'clock yesterday morning, at this moment last Sunday上周日的这个时候...