(1)可以(表示许可)(used to ask for or give permission)：M～I leave now/I take a swim/I have a word with you?我现在可以走/游泳/与你说句话吗? You～go shopping/say what you please/use my car.你可以去购物/想说什么就说什么/用我的车子。No one～enter without a ticket/borrow up to 5 books at any one time.任何人无票谢绝入内/一次至多借五册书。I'll take a seat，if I～. 要是可以的话，我就坐下了。

(2)可能，也许(表示可能性)(used to express possibility)：This～be true.这可能是真的。It～rain this afternoon.午后或许有雨。There～be side effects from the new drug.新药也许有副作用。Matthew～have been there before.马修以前也许去过那里。A gigantic meteorite～have wiped out the dinosaurs 65 million years ago. 6500万年以前，也许是一块巨大的陨石使恐龙灭绝。

(3)能，以便(表示目的)(indicating purpose)(用于so that，in order that之后)：I make my stories lovely and simple so that the smallest child～enjoy them.我把故事写得生动、易懂，好让最小的孩子也喜欢。People struggle to cure diseases so that they～live longer.人们努力治疗疾病以期能长寿。Stand where you are，so that I～see your face clearly.站在原地别动，让我看清楚你的脸。

(4)会(用于询问)(used for asking for information)(旧用法)(含有无把握，或高傲的口气)：Who～the man be?这人会是谁呢? How old～you be? 你的年龄会有多大呢?

(5)祝愿(表示希望，愿望)(used to express a wish or a hope)：M～you both always be very happy!祝二位永远幸福。M～the best man be in good health.祝愿那位最好的人健康。Long～the peace in the world continue.愿世界永久和平。

may/might(just)as well(do sth)不妨：If that's the case，I～as well try.如果情况如此，我不妨试一次。Since it's a fine day we might as well walk.既然天气很好，我们不妨走一走。

may well很可能，有充分理由：You～well say so.你完全可以这样讲(话)。Your eyesight～well improve.你的视力很可能会好转。

【用法】may(旧用法)和might都含有不肯定或傲慢的口气，用于询问情况如：Well，and who may/might you are?(好啦，你会是谁呢?)在间接用语中只用“might”。