Question

must have done什么意思?

Answer 1

must have done sth.一定做某事。表示对过去事情的较有把握的推测，这时只能用在肯定句中，“肯定/必须已经干过…”，在否定句和疑问句中用can't或couldn't或can/ could，
例如：
1.From what you said, she must have told you all about it.
从你的话看，她一定告诉了你所有的事情。
2.The light was out. They must have gone to bed.
灯都熄了，他们必定睡了。
3.He must have done it when I was off with those assholes.
他一定是趁我和那群混蛋一起的时候做的。
4.The man must have done something right, more right than all jumpers before.
这个人一定是做了些很对的事，比所有以前跳高的做得更对。
5.China must have done something supremely right to produce the economic miracle we observe.
中国一定是做了非常对的事才产生了我们见到的经济奇迹。
6.You must have done something to her.
你一定有跟她做什么事。
7.He must have done sometime. Certainly he had always been jealous of him as a child.
有时他肯定爱，当然他总是忌妒弟弟，像一个小孩子。

Answer 2

“must have done”通常指过去发生了某件事情并且很可能被认为是真实的或必然发生的。它表示对某个事件的推断或假设，并不一定意味着它确实发生了。