问题描述: He can't have been.He must have been.不是说单三用has吗?这里怎么用的have? 1个回答 分类:综合 2014-12-08 问题解答: 我来补答 正确答案为:在情态动词(can't,must)后面动词要用原形have.★☆★☆★☆★☆★☆★☆ 展开全文阅读