must have done，must do，can't have done，can't do的区别

Question

如题所述

Answer 1

must have done对过去发生的动作很有把握的肯定推测
must do“必须做”，含有一种命令的口吻，语气强
can't have done对过去发生的动作很有把握的否定推测，意为“不可能做了”
can't do“不能做”表示不给予许可，语气没有must do强

Answer 2

must have done, 对过去行为的肯定推测：（过去）一定；肯定；必定（做过……）
You must have gone to school yesterday because it was Friday.
= I am sure you went to school yesterday...
can't have done 是 must have done 的否定形式，即对过去行为的否定推测：（过去）肯定没有，一定没有……
You can't have stayed at home yesterday because it was Friday.
must do 表示现在或将来的义务、责任、法律规定：必须、应当、应该……
Everyone must obey traffic rules.
can't do 表示现在的能力:不能、无法
You can't finish such hard work in such a short time.

Answer 3

must have done 表示对过去的猜测,must do 必须做某事，can't have done本不应该做某事而已经做了。can't do不能做。追问

有例句么？

Answer 4

must have down表示对过去肯定的推测
must do 表示对现在肯定的推测
can't have down表示对过去否定的推测
can't do 表示对现在否定的推测