從零開始學語法：may have done用法小結
may/might have done 推測過去
“may/might+動詞的完成式”表示對過去發生的行爲的推測。例如：
-Whatever has happened to George?
-喬治發生了什麼事?
-I don't know. He may have got lost.
-我不知道，他可能迷路了。
You might have read about it in the papers.
你可能在報上已經看過這個消息了。
（之前我們做過can have done用法小結，can have done表推測時都是對過去進行推測，但是may have done不僅可以推測過去）
may/might have done 推測現在
“may/might+動詞的完成式”表示對現在情況的推測。例如：
She might have got up now.
現在她可能已經起牀了。
may/might have done 預測未來
“may/might+動詞的完成式”表示推測將來某時之前的情況。例如：
He may have left when you get there.
等你到達的時候他可能已經離開了。
注意：may have done 和 might have done 表推測時，might 所表示的可能性比 may 小，語氣較委婉：
How quickly time passed! It might have happened yesterday.
時間過得好快啊！這事好像就發生在昨天。
He might have seen the surprise in my face.
他或許已經看到了我驚異的表情。
might have done 表輕微責備
might have done 除了能夠表推測，還能表示過去本來可以做而實際並沒有做。這時帶有輕微的責備之意。例如：
The proposal might have been refused.
這個建議本該拒絕的。（有輕微的責備之意）
I might have taken another path.
我本可以走另一條路。
may not/mightn't have done 表“可能不”
之前我們講到過 can't/couldn't have done 是表示“不可能”，而 may not/mightn't have done 則是表示“可能不”，要注意區分哦：
He can't have been at the meeting, he's on a business trip this week.
他不可能有出席會議，他這周出公差。
We couldn't have done it without you.
沒有你我們肯定完成不了。
They may not have known it beforehand.
他們事先可能不知道這事兒。
They mightn't have regarded me as their friend.
他們可能沒有把我當作朋友看待。
