请问十分重要的英语问题!

must have done 对过去发生事情的肯定推测,过去一定做过某事,
其否定形式can't have done不可能做够某事

The ground is wet.It must have rained last nignt.

Isaw lily on the bus this morning .She can't have gone abroad.

must not "禁止”

should have done 本来应该做某事，而实际上却没有做，含有责备，惋惜的语气
The flower was dead.I should have watered it.(实际上没有浇花，花死了，含有惋惜的感情色彩）
I failed to pass the exam.I should have studied hard.
shouldn't have done 本来应该做某事，而实际上却没有做，同样含有责备，惋惜的感情色彩）
I shouldn't have told him the truth.(责备）
might have done 可能做过某事，对过去可能发生事情的一种推测，可能性比较小，其否定式might not have done
may have done 和might have done 所表示的意思差不多，只存在语气上的差异，may have done 的可能性要大些

needn't have done
本应该做某事（实际上没做）
本不应该做某事（实际上做了）should (not) have done都有责备的意思
过去也许做了某事 否定我也不知道 好象没有may have done

这些都是过去虚拟语态
must have done 意思是"一定已经做了"(但事实是有可能没做)
should have done 应该做而没做

shouldn't have done 不应该做却做了

might