英文文法专题讨论是版主汇整目前个人仍觉困扰的项目，将其独立出来，以便日后可随时参考。这些属于必要但高级的文法课题，如有需要版主会随时贴文。本篇浅谈英美人士如何用时态来说明过去可能发生，却没有发生的事情，以及过去实际有可能发生的事情。

1. 过去可能发生、但实际上却未发生的事情

That was a bad place to go skiing – You could have broken your leg.
(那个地方不可滑雪，搞不好会摔断腿，幸好你没有。)  – 去滑雪了，但没有摔断腿

Why did you throw the bottle out of the window? Somebody could have been hurt.
(你为何要将瓶子丢出窗外？有可能到砸到人，你知不知道？) – 丢了瓶子，但没有砸到人

I have a brilliant publisher who never went to university – he just started working when he was young and he worked hard and did very well. He would never have got that job nowadays because he would have had to have gone to a really good university and got good results to get a job here.
(话中主角已经得到工作，这句话是假设过去未发生的情况。)

(比较)
He may/might not have understood. (= Perhaps he didn’t understand.)
(他可能不瞭解。)

He can’t /couldn’t have understood. (= He certainly did not understand.)
(他绝对不瞭解。)

2. 过去可能发生的事情

Where can she have gone? She can’t have gone to school – it’s Saturday.  And she can hardly have gone to church. She may/might have gone swimming, I suppose.
(她可能会去了哪里呢？今天是礼拜六，她不可能去学校。她也不太可能去上教堂。我想，她可能去游泳了。)