情态动词have done结构（情态动词cancouldhave）

1.can/could have done sth.本来能够做某事，而实际上未做；做了……就好了；想做……（可是）；可能会……可能是（对过去发生的事情不太肯定的推测）

经典例句：

'Welcome back' was all they said. I could have kissed them!

他们只是说，“欢迎回来。”我真想亲他们一下！（可是没有亲）

You could have reviewed, but you played games all night.

你本可以复习的，但你一晚上都在玩游戏。（可是没有复习）I could have wept thinking about what I'd missed.

想到所失去的东西，我真想痛哭一场。（忍住了，没哭）

He'll kick himself when he finds out he could have had the job.

一旦发现他本可以得到这个工作，他会感到懊恼的。（实际没有获得这个工作）

The accident could have been prevented.

这次事故本来是可以防止的。（实际上事故发生了）

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。（实际上没有得救）

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。（实际上没有帮助）

Events could have developed in a dramatically different way.

事情本来可以发展成另一种样子。（实际上事情没有发展成另一个样子）

Really, you could have told us before.

真是的，其实你大可事先跟我们说一声的。（实际上并没有事先说）

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。（实际上我没有去赢）

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。（实际上没有去索取）

But we could have done it all so much better.但是，我们本可以把这一切做得更好。（实际上没有做得更好）

The resources at our disposal could have been better utilized.

我们所掌握的资源本来可以利用得更好，获得更高的效益。（实际上没有利用好而获得好的效益）

It's not funny! Someone could have been hurt.

这没什么好玩的！可能有人会受到伤害。（实际上还没有人受伤）

Her hair could have done with a wash.

她的头发该洗一洗了。（实际上没有洗头）

You could have spared yourself an unnecessary trip by phoning in advance.

你要是先打个电话就用不着跑这一趟了。（实际上先没有打电话）

Don't worry ─ they could have just forgotten to call.

别担心，他们可能只是忘了打电话。（多了一个 just，仅仅，实际上是对过去发生的事不太肯定的推测，个人观点，请大神指点）

The lights were out. They must have been asleep. 灯灭了，他们应该睡觉了。（对过去发生的事比较肯定的推测）

2.can't/couldn't have done sth.不可能做过某事

经典例句：

He can't have slept through all that noise.

他不可能在那种闹哄哄的环境里睡好觉。

From her knowledge of Douglas's habits, she feels sure that the attacker can't have been Douglas

根据她对道格拉斯习性的了解，她敢断定他不可能是那个袭击者。

Keep looking ─ they can't just have vanished off the face of the earth.

继续找——他们不可能就此从地球上彻底消逝的。

You couldn't have left it on the bus, could you?

你不可能把它落在公共汽车上了吧？

It couldn't have been me ─ it must have been someone else.

那不可能是我——准是别人。

The damage couldn't have been caused accidentally.

这次损毁不可能是偶然因素造成的。

I could't have done it without you.若是没有你，我不可能做到那样的。

We could't have done it without you.没有你我们办不成这事。

No one could have predicted the final outcome.

谁也没有预想到最终结果会是这样。

It couldn't have cost more than £ 50, tops.

这东西的价格最高不会超过50英镑。

He couldn't have been more than fourteen years old.

他不可能超过14岁。

Suddenly it dawned on me that they couldn't possibly have met before.

我突然明白他们以前不可能见过面。

If he hadn't shot his mouth off, things couldn't have been so awkward.

要不是他多嘴，事情也不至于搞僵。

This was an extremely successful trip. It couldn't have been better.

这次旅行玩儿得真过瘾。

The news couldn't have come at a better time.

那消息来得正是时候。

Career-wise, this illness couldn't have come at a worse time

考虑到事业，这场病来得最不是时候。

最后两个例句也是来自词典，值得仔细推敲。

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