could have been done ,could have done各有什么意思
could have been done ,could have done各有什么意思
来个都是虚拟。
could have done是主动，本来可以做而实际没做；
could have been done是被动，本来可以被做而实际没被做的。
could have done什么意思
could have done
本来能做成的（却没做成）
双语例句
1.
But we could have done it all so much better.
但是，我们本可以把这一切做得更好。
2.
If you do a good job, you may tell yourself that it wasn’t good enough or that anyone could have done aswell.
比如你完成了一项出色的工作，你或许告诉你自己它不够好，任何人都可以做的像你一样好。
本不该做却做了
意思是：（当时就）可能做了；言外之意是，当时没做。
这是虚拟语气的一种用法。举一个例句，就会更加清楚地了解这种用法：
If we had had the money, we could have had a good time.
如果当时我们有钱的话，我们本能玩的很愉快的。
这种用法，是“询问/谈论想象当时的情况或者是结果”。再如：
If I had lost my job, I would have gone abroad.
假如我当时失业了，我就会到国外去了。（言外之意，我没有去，当时也没有失业。）
could have done和need have done是什么意思
need have done 是表示需要做某事却没有做。could have done本能做某事却没有做(不含谴责意味），拓展。。should have done本能做某事却没有做(含谴责意味）eg;I should have passed the exam if I did not stay up.
请问could /ought /would have done各什么意思？
could have done 本能够，有能力去做，但事实没去做 be ought to have done 本应该，事实没 would have done 本会去做，事实没 多用于：if +过去时， *** ~/~/~ sth.还有其他用法，根据语境确定
could not have done是什么意思
could not have done
不可能做
例句
1.Had they not helped us, we could not have done It'so suessfully.
如果没有他们的帮助, 我们不可能把那件事办的如此成功.
2.Without his help, we could not have done the work quickly.
要是没有他的帮助, 我们的工作就不会很快完成.
3.Without your help, we could not have done the work well.
如果没有你的帮助, 我们不可能把工作做好.
两个都是，但常表示“本不能做某事却做了”。
表示“不可能做某事”是对过去事情的推测。
eg：He couldn't have failed the exxam,and he studied hard recently.
