情态动词can't have done 和couldn't have done 有什么区别吗

来源：学生作业帮编辑：拍题作业网作业帮分类：英语作业时间：2024/04/30 15:02:23

情态动词can't have done 和couldn't have done 有什么区别吗
对过去发生的事情否定猜测用can't have done 或couldn't have done ,两者有区别吗?
比如 He can’t have gone to Beijing for I saw him a minute ago. 能换成He couldn’t have gone to Beijing for I saw him a minute ago.吗?
谢谢

can't have done（不可能做过）是must have done（一定做过）的否定形式.
couldn't have done(可能没做过)是may have done(有可能做过)的否定形式.
一般认为can't have done有80%以上的把握.而couldn't have done则委婉的多,只有50%左右的把握.
must do /can't do一定,肯定80%把握
may/could do/couldn't do有可能50%把握
might do/mightn't do也许大概差不多30%以下的把握

情态动词can't have done 和couldn't have done 有什么区别吗 couldn't have done和mightn't have done有什么区别 can have done和could have done有无区别?can't have done和couldn't h 有没有can have done sth?could have done sth有两种意思吗?can't/couldn' couldn't have done? 1、shouldn't have done mustn't have done can't havedone 有什么区别 couldn't have done 有不可能的意思吗?问题二它和cant have done的区别 can't have been和can' have done有什么区别 can have done和 could have done有什么区别? couldn't have done与couldn't区别 couldn't have done 表示什么区别shouldn't have done 和 needn't have done