He must have finished the work by himself by the end of last mont_英语解答

He must have finished the work by himself by the end of last month,____he?
为什么填hadn't啊?为什么不填hasn't?为什么不填didn't?
原句是must have ……,也就是说是现在完成时,那应该填hasn't啊,但为什么不填这个?
什么时候又可以用didn't?

人气：373 ℃　时间：2019-09-09 17:28:41

解答

要根据整个句子的时间状语来选择这类反意疑问句的助动词.1.如果没有任何时间状,可以用have或has.eg.He must have gone to the library,hasn't he?2.如果有表示过去的时间状语则用did.eg.He must have read this book...