Did she do her homework last night?(用at seven o'clock last night代替last night)

问题描述:

Did she do her homework last night?(用at seven o'clock last night代替last night)
解释为什么要这样改

应该是:
Was she doing her homework at seven o'clock last night?
昨天晚上七点她在做作业吗?
at seven o'clock last night 昨天晚上七点,是一个时间点
所以在那个点应该是正在做什么
所以用过去进行时