mustnt have done与cant have done区别啥区别

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mustnt have done与cant have done区别啥区别

mustnt have done与cant have done区别啥区别
mustnt have done与cant have done区别
啥区别

mustnt have done与cant have done区别啥区别
1.情态动词must+have done只用于肯定句中,表示对过去发生的事情或状态进行肯定的推测,意为”过去一定做过某事”.
如:
1)It must have rained last night,for the road is all wet.
昨天晚上一定是下雨了,因为路还湿着.
2.情态动词can/could可用于否定句中,即can't have done/couldn't have done,表示对过去发生的事情或状态的肯定的推测,意为“过去不可能做过,肯定没做过”,与musthavedone正好相反.
如:
1)He can't have taken it home.
他不可能把它带回家.
一般来说,没有must not have done的用法