could done
could have done与could do区别
could have done与could do区别 因为是已经过去了的事情，所以用could，而非can；因为是完成了的事情，是完成时，所以要用have。简单地说因为是上个星期，而且是事情已...
【英语学习】语法贴士 第二期 Could do 和 Could have don...
Could do 用于描述过去的能力或可能性，而 Could have done 用于描述实际上未发生但有可能发生的情况。Could do 的应用： 描述过去的能力：当你想表达过去某个时间点你...
...have donecould have donecould not docould do...
could not have done是情态动词的虚拟用法,本来不能做某事,但实际上做了.could have done是情态动词的推测用法,是可能已经做了.could not do 是情态动词的基本用法,不能...
这个句子里的could have done和 could not have done...
could have done更倾向于表达“本可以做但是实际上没有做”，但是不绝对，你仍然可以说“本来就可以做这件事，所以我就做了”。He asked him...
could have done和could do有什么区别?
could have done不能表推测，是虚拟语气，固定搭配。could do能做什么，不能表猜测。can:用于否定句或疑问句中表猜测，常见于否定句中。如：That can't be him.Beacus...
could have done的各种用法(在肯定句,否定句,疑问句中...
“could+have+done”是虚拟语气,表示对过去事情的假设,意思是本来能够做某事而没有做. He could have passed the exam, but he was too careless. 本来他能够通过考试,...
...have done,could have done,may have done,might...
解答情态动词表示猜测的试题时,一要清楚被猜测的时间,二要清楚有无客观事实根据.若有客观事实根据,则无论是肯定还是否定的猜测,猜测语气最强且符合时间要求的为最佳答案;情态...
虚拟语气would/could/should/might have done 之间的...
could have done，表示：①对过去某种情况的怀疑或者是不确定（情态动词推测用法）；②过去本来可以做某件事，但是实际上却没有做（虚拟语气用法...
could have done sth 和must have done sth 的区别是...
如:He could have been very rich,but he cared for no money at all.must have done 对过去的动作的推测.如; You must have seen him yesterday.你昨天一定看到他...