特殊疑问句 What was he saying yesterday?他昨天说什么?一般疑问句 Were they doing their homework at that moment?他们在那时做作业了吗?肯定句 I was finishing my homework at night.我昨天晚上写完我作业了,否定句 She wasn't watching TV at that time.她在那时没有看电视.