1. must have done过去一定做了某事（对过去的事情一种肯定的猜测、推测），如：
He said I must have done something bad to deserve it.
他说我肯定是罪有应得。
That car must have cost a packet.
那辆汽车一定花了一大笔钱。
I think we must have taken a wrong turning somewhere.
我觉得我们一定是在什么地方拐错了路。
He must have fallen from a great height.
他肯定是从很高的地方摔下来的。
He must have known what she wanted.
他一定早已知道她想要什么了。
That car must have cost a bundle.
那部车一定价格不菲。
That dress must have cost a bomb!
那条连衣裙所费不菲吧！
She reasoned that she must have left her bag on the train.
她断定准是把包落在火车上了。
The car must have been doing at least 100 miles an hour.
这车速肯定每小时至少100英里。
Your cheque must have got lost in the post.
你的支票一定是邮寄中遗失的。
I must have been blind not to realize the danger we were in.
当时我一定是眼瞎了，竟然没有意识到我们所处的危险。
To qualify, you must have lived in this country for at least three years.
你必须在这个国家居住至少三年才能享有此权利。
Your trip must have been fun!
你这次旅行一定很开心吧！
Judging by the company he kept, Mark must have been a wealthy man.
根据马克所交往的人来判断，他一定是位富翁。
You must have wiped off that programme I recorded.
你一定是把我录制的节目给抹掉了。
Sorry, I must have dialled the wrong number.
对不起，我一定是拨错电话号码了。
The lights were out. They must have been asleep. 灯灭了，他们应该睡觉了。
I can't remember any more ─ I must have lost consciousness.
我想不起来了——我当时一定是失去了知觉。
高考真题在线解析：
He must have completed his work；otherwise，he wouldn’t be enjoying himself by the seaside．(高考试题)他肯定完成了工作，否则他就不能在海边开心了。 -Guess what!I have got A for my term paper． -Great!You_______read widely and put a lot of work into it．(高考试题) A．must B．should C．must haveD．should have【解析】答案为C。从对话上来看，此处应该是对过去动作的推测，A和B是对现在或将来的推测，应排除；而D指过去本应该做而未做的事，语境不符。 -She looks very happy．She___________have passed the exam．(高考试题) -I guess so It’s not difficult after all． A．should B．could C．must D．might【解析】答案为C，因为考试不难，她又看起来很高兴，所以推测语气非常肯定。 The teacher_________have thought Johnson was worth it or she wouldn’t have wasted time on him，I suppose．(高考试题) A．shouldB．canC．would D．must【解析】答案为D。老师一定已经认为Johnson是值得的，我认为，否则她就不会在他身上浪费时间了。 温馨提示：此句型只用于肯定句中，否定结构中常用“can’t have done”(表示“不可能…”）或“may not have done”(表示“可能不…”)
2.mustn’t have done用法罕见，不讨论。
如果非要表示对过去的事情否定的推测可以用：
can have done用于否定句和疑问句，表示对过去情况发生的可能性的否定或质疑，意思是“可能已经…了吗?”或者是“不可能／不会已经…的”：
高考真题在线解析：My MP4 player isn’t in my bag．Where______I have put it？(高考试题)A．canB．mustC．should D．would【解析】答案为A。这是疑问句，所以排除B选项，另外,should have done意为“本应该…”，所以排除,would have done表示虚拟语气，所以也排除，A的意思为“我可能把它放哪呢?” He can’t have gone to Japan for I saw him at the meeting just now． 他不可能去了日本，因为我刚刚在会上见到他了。
Can he have finished the work so soon? 他会这么快完成这个工作吗?
另外：
could have done既可以表示虚拟语气又可以表示对过去情况的推测
If only I could have helped put matters right.
要是我当时能帮着把错误纠正过来就好了。（虚拟语气）
There's no denying that quicker action could have saved them.
无可否认，如果行动快一点，本来是救得了他们的。（虚拟语气）
常用来表示过去本来可能或能够做到，但由于某种原因实际上并未做到，意为“本来能够…，本来可以…”，含有责备语气。
I could have won the game but decided to let her win.
我本可以赢得那场比赛，但还是决定让她赢了。
You could have claimed the cost of the hotel room from your insurance.
你本可以从你的保险中索取旅馆住房费。
-Did you visit the famous museum?-No，we could have visited but we spent too much time shopping。(虚拟语气) -你们参观那个著名的博物馆了吗? -没有，我们本来可以参观的，但我们花太多的时间买东西。用来表示对过去情况的推测 I could not have been more than six years old when the accident happened．(高考试题) 当那次事故发生时，我不可能超过6岁。（表示对过去否定的推测） That was not a good place for skating．You could have broken your leg．(表示对过去肯定的推测) 那不是一个滑冰的好地方，你有可能摔伤腿的。
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