may和might可以表示可能性和许可。might的语气比may较婉转。此外，may也可以接动词的完成形式，表示可能、说不定已经做某事。
【例如】
I thought it might be difficult for me to learn advanced mathematics. （可能性）
May I come in, sir? （许可）
She may have gone to the hospital.
Research findings show we spend about two hours dreaming every night, no matter what we ____during the day. (cet-4 1999,1)
A) must have done
B) should have done
C) would have done
D) may have done
情态动词后面加动词完成式，有不同意义。
must have done表示一定做过某事；
单词：May的近义词、反义词、形近词辨析
must/have to/be forced to/may/can/should/be supposed to/shall
记忆；
1. must [ mQst; mEst] aux. 必须, 应当, 很可能, 一定 -Must I finish it at once? – No, you needn’t.“我必须马上做完吗？”“不必。”
2. have to 不得不, 只好（客观原因所致）We had to put off the sports meet because of the rain. 由于大雨，我们不得不推迟运动会。
3. be forced to 被迫 Karl Marx was forced to move on again.卡尔马克思被迫再次搬迁。
4. may [ mei, me ] aux. 可能, 也许, 可以, 祝 May I help you?要我帮忙吗？
5. can [ kAn, kEn ] n. 罐头, 铁罐 conj. 能, 可以 He can’t have gone to Xi’an, for I saw him in the office just now. 他不可能到西安去了。我刚才在办公室还看到他。
6. should [ Fud, FEd, Fd ] v.aux.应该, 将要 The radio should be ready at that time.那个时候收音机应该已准备好了。
7. ought to v.aux.应该, 将要 You ought to have done your duty yesterday.你昨天就该完成你的任务。
8. be supposed to 应当 The passengers are supposed to get on the train in order.乘客应该有秩序上车。
9. shall 将(用于第二、三称时表示允诺，第一、三人称可表示征求对方意见) -You shall get a bike for your birthday. – Thank you, Mum. Shall Li Ping share it with me? “你生日时会得到一部自行车。”“谢谢你，妈妈。可以让李平与我共享那部自行车吗？”
另类阅读：
You may/can go home now. I have to stay because the teacher said I should help clean the classroom. I must obey him, otherwise, I will be forced to do more cleaning tomorrow.
与单词：May 相关的例句或者名人名言
A comrade may save your life in the war.
在战争中，战友也许会救你的命。
Please, miss, may I go to the toilet?
小姐，请问我能去下厕所吗？
They may be old, but they're still as lively as ever.
他们也许已经年老，但仍然有活力。
"I may bleed to death." were the watermelon's last words.
“我可能要流血身亡了。”西瓜哥留下遗言。
That may or may not be true .
那可能是真的，也可能不是真的。
※A state which dwarfs its men ,in order that they may be more docile instruments in its hands even for beneficial purposes will find that with small men no great thing can really be accomplished.——John Stuart Mill, British economist 一个政府压制它的人民，以使他们成为自己手中的驯服工具——即便是为了正当的目的——它也会发现，靠受压制的人是不可能真正成就什么大事的。英国经济学家 穆勒J.S.
※In war, whichever side may call itself the victor, there are no winners, but all are losers.——Nerille Chamberlain,British prime minister 战争中只有输家，没有赢家，尽管双方不论哪一方均可能自称为胜利者。英国首相 张伯伦，N。
※We shall defend our island, whatever the cost may be . We shall fight on the beaches, we shall fight on the landing-grounds, we shall fight in the fields and in the streets, we shall fight in the hills; we shall never surrender.——Winston Churchill British prime minister 无论需要付出多大的代价，我们也要捍卫我们的岛国。我们要战斗在海滩，我们要战斗在登陆地带，我们要战斗在田野、街巷，我们要战斗在山冈、丘陵，我们决不投降。英国首相 丘吉尔， W。
※If you don't learn to think when you are young , you may never learn .(Thomas Edison , American inventor )——如果你年轻时就没有学会思考，那么就永远学不会思考。(美国发明家 爱迪生 . T.)
