couldn't have done和mightn't have done有什么区别
couldn't have done和mightn't have done有什么区别
情态动词can't have done 和couldn't have done 有什么区别吗
couldn't have done?
看很多书上说,couldn't/mightn't have done没有虚拟的意思.那么
can have done和could have done有无区别?can't have done和couldn't h
couldn't have done与couldn't区别
couldn't have done 表示什么
couldn't have done 有 不可能的意思吗?问题二它和cant have done的区别
区别shouldn't have done 和 needn't have done
1、shouldn't have done mustn't have done can't havedone 有什么区别
should have done和shouldn't have done,couldn't have
couldn't have done,"不可能已经"?