couldn't 是can't的过去词吗?
couldn't 是can't的过去词吗?
couldn't是can't的过去式吗
can't与couldn't的区别
couldn't与can't的区别!
can't与couldn't 的用法
can’t / couldn’t have
can't和couldn't
cannot can't couldn't mustn't的问题
couldn't是过去式吗
用can、can't、could、couldn't写一篇关于自己的短文 不少于60词
He said he couldn't follow me.句中couldn't能换成can't吗?
can't too与couldn't too的区别