(1)可以(表示允许)(indicating permission or a request for permission)(在疑问句中有怀疑、羞怯的含义)：M～I ask a question/make a suggestion/borrow a book? 我是不是可以问一个问题/提一个建议/借一本书? I wondered if I～see the letter. 不知道我可不可以看看那封信。The boy asked if he～have a quick look at the newspaper. 孩子问他可不可以浏览一下报纸。

(2)可能，也许(表示可能性)(indicating possibility)(比may更含怀疑、犹豫的含义)：He～know Tom's address/emigrate to Australia/get home in time.他或许知道汤姆的住址/可能移民去澳大利亚/也许能及时赶回家。The king～do nothing without parliament's consent.没有国会的同意，国王或许什么也干不了。If she were older she～understand.要是她年纪大一些的话就会懂了。You～have caught the bus if you had run.要是跑着来，你就会赶上车了。She～just possibly have lost her job.她有可能把工作丢了。

(3)能，以便(表示目的)(indicating purpose)(用于so that，in order that)：We carved their names on the stone so that future generations～know what they had done.我们把他们的名字刻在这块石头上，以便后代能知道他们做的事。

(4)会，用于询问(asking for information，expressing humour，etc)(含有无把握或高傲的口吻)：What～she want? 她究竟要什么呢? And what～that mean? 那是什么意思? Who～he be? 他会是谁呢? Nobody said who he～be.没有人说他可能会是谁。

(5)请(表示婉转的请求)(used in making polite requests or appeals)：I thought you～like to join me for dinner.我想你会愿意和我一起吃晚饭。

(6)应该(表示婉转的责备)(suggesting that a person is not doing what he should)：You～at least apologize/call.你至少应该表示歉意/打个电话。You～have told me before/helped us earlier!你本应该提前告诉我/早点帮助我们!

might (may) (just) as well (do sth)不妨，还是……好，最好：You～just as well go by train instead of by plane.你最好坐火车，不要乘飞机去。

【辨异】might与can、could 和may的区别见CAN。