can't have been和must have been
问题描述:
can't have been和must have been
答
只要记住这: must have been ... 那时一定是can't have been... 那时不可能是 再好好理解这几人句子,相信你就理解啦. He can't have been ill. He must have been tired. She can't have been forty. She must have ...