may和might的区别及用法

一、表示允许　　
其意为“可以”.表示请求允许(即请求别人允许自己做某事),两者都可用,只是 might 表示的语气较委婉(但并不表示过去)；表示给予允许(即自己允许别人做某事),通常要用may而不用might.如：
May (Might) I come round in the morning?我早上来可以吗?
“May I take this book out?” “Yes,you may.” “我可以把这书带走吗?”“唔,可以.”(由于答语是表示给予允许,可用 may,但不能用 might)　　
You may take my dictionary as long as you don’t keep it too long.只要使用时间不太长,你可以把我的词典拿去.(不用might)　　
二、表示推测　　
may 和 might 均可表示推测,意为“可能”.此时 might 并非表示过去,只是比may 语气更不确定,表示的可能性更小.两者均可用于肯定句和否定句,但用于疑问句时,may 通常不用于句首,而 might 有时可用于疑问句的句首.如：
He may (might) be in his office now.他现在说不定在办公室里.
You may (might) be able to persuade him.你也许能说服他.
Might it rain tonight?今晚会下雨吗?
要表示对过去的情况进行推测,不能用“might+动词原形”,必须用“may / might+have+过去分词”结构.如：
I may have hurt your feelings but that was certainly not my intention.我或许伤害了你的感情,但那绝非我的意图.
There may (might) have been someone waiting outside.可能曾有人在外面等候.
另外,“might+have+过去分词”还可表示过去可能发生而实际上却并没发生的事(此时的might不能换成may).如：
In other circumstances,I might have agreed.在其他情况下我可能就会同意的.
I might have guessed he’d fail to read the instructions.我本来早该知道他不会看说明书的.

情态动词may和might有哪些不同

may是情态动词，表示“可能”或“可以”，后接动词原形，构成谓语动词。它有两种形式，原形为may，过去式为might。
may的基本含义是表示“可能”，即不很肯定的推测，或者表示“可以”，即允许做某事的意思。指现在时，可以用may，may还可以表示祝愿，may一般不用于疑问句，用在疑问句中时，表示询问情况，含不肯定的语气，例如：
He may be right.
He may be watching TV.
May I leave the table?
May I never see such a sight again!
May you succeed!
Well, and who may you be?
How old may she be?
It may have rained yesterday. The ground was wet.
如果表示过去可能或可以做某事，就用may的过去式might，might用于疑问句的时候，也可以表示询问情况，或用在间接问句中。might常用在主句为过去式的名词性从句中，如果用在独立句中，语气比may更不确定，把握性更小。如：
He said that it might be true.
He asked whether he might leave the table.
Bill asked who she might be.
The keys might have fallen out of your pocket.

may ,might 或许,可能,可以
（might可以看作是may的过去式,这两个词除了时态不相同外,在表达意思的许多方面是相近的.当然may 和might又都有一些各自不同的独特用法.）
1）可能性
I may be busy from tomorrow on .从明天起我可能会忙起来.
You may catch sight of the sunrise from here when you get up before 5 in the morning .你在早晨五点钟以前起来,或许能从这儿看到日出.
I wondered if they might agree with the idea .我想知道他们是否会同意这种想法.
She thought it might be wise to try her luck here .
她认为在这儿碰碰运气也不错.
2）表示允许
May I come in 我可以进来吗?
I'd like to have a smoke here if I may .
如果可以的话我想在这儿抽一支烟.
The librarian told her that she might return the book to the library in three days .
图书馆理员告诉她说,她可以在三天后还那本书.
At the press conference ,a news reporter asked the chairman if she might trouble him with a question about Taiwan issue.
在记者招待会上,一位新闻记者问大会主席她是否能提一个有关台湾问题方面的问题.
3) may间或用来表示祝愿,也常用于表示目的或让步的状语从句中:
May that day come soon .但愿这天早日到来.
May you succeed in winning the first prize in the game .
祝愿你比赛夺冠成功.
May you continue in your efforts and achieve greatersuccesses .
祝愿你继续努力并取得更大的成功.
4) might也常用于表示目的等状语从句中,或用于虚拟语气的结构中:
I could not convince him ,try as I might .我无论用什么样的办法也不能说服他.
They left off earlier on that day so that they might catch the first train .
那天,他们为了赶上头班车动身早一些.
He died so that the others might live .
为了其他的人能活下去,他自己牺牲了.
If you had made better use of your time ,you might have learned more .假若你将自己的时间利用得更好一些,你本可以学到更多东西的.
One error in calculation might ruin the whole project .
计算中出一点错就可能毁掉整个工程.
注意：在回答以may引导的问句时,一般说来避免使用may,以免显得太严厉、或不太客气,而改用其他方式.例如：
--May I come in --Yes ,please .请进.
我可以进来吗?--Sure ./ Certainly ..请进.
--Please don't ..请不要进来.
--No ,you mustn't .不行.
引用自：https://www.zybang.com/question/f874ab5ddf96e2cb82bd8044695c69e5.html