“may(might)+動詞的完成式”表示“對過去發生的行為的推測”。

　　may have done 表推測時，隱含“不確定”。

　　might have done 表推測時，隱含的“不確定性”比“may have done”更深。

　　He may not have finished the work.

　　他可能還沒有完成那項工作。

　　They may not have known it beforehand.

　　他們事先可能不知道這事兒。

　　You might have read about it in the papers.

　　你可能在報上已經看過這個消息了。

　　-Whatever has happened to George?

　　-I don't know. He may have got lost.

　　喬治發生了什么事?

　　我不知道,他可能迷路了。

　　might 表示的可能性比may小,語氣較委婉。例如:

　　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。