英文文法專題討論是版主匯整目前個人仍覺困擾的項目，將其獨立出來，以便日后可隨時參考。這些屬于必要但高級的文法課題，如有需要版主會隨時貼文。本篇淺談英美人士如何用時態來說明過去可能發生，卻沒有發生的事情，以及過去實際有可能發生的事情。

1. 過去可能發生、但實際上卻未發生的事情

That was a bad place to go skiing – You could have broken your leg.
(那個地方不可滑雪，搞不好會摔斷腿，幸好你沒有。)? – 去滑雪了，但沒有摔斷腿

Why did you throw the bottle out of the window? Somebody could have been hurt.
(你為何要將瓶子丟出窗外？有可能到砸到人，你知不知道？) – 丟了瓶子，但沒有砸到人

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.
(話中主角已經得到工作，這句話是假設過去未發生的情況。)

(比較)
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.)
(他絕對不瞭解。)

2. 過去可能發生的事情

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.
(她可能會去了哪里呢？今天是禮拜六，她不可能去學校。她也不太可能去上教堂。我想，她可能去游泳了。)