高中英语情态动词的用法有哪些?我了解了一些,但内容很多,还是不能系统地掌握.

情态动词的考点精简
一、何谓“情态动词”?
情态动词主要用来表示说话人的情感、态度等,是中学英语语法的重点,也是高考的热点,是单项填空必考的一个知识点.高考试题常常借助语境和句子之间意义上的细微差别来考查学生对情态动词的基本用法及其区别,近五年高考中主要考查四点：情态动词表示推测和可能性的用法；情态动词与虚拟语气；情态动词的表达“情感、态度、语气等”,情态动词表示 “必要性”等方面的用法.
二、情态动词的特点
1.没有人称和数的变化.
2. 有些情态动词有过去式的变化:
e.g. will → would , can → could , may→ might , dare → dared
三、情态动词的否定形式
情态动词+ not +动词原形can not: can't , must not: mustn't , need not : needn't
四、情态动词的用法（常考考点）
Shall
一）用于一、三人称疑问句中,表示说话人征求对方意见和向对方请示.
Shall we begin our class? Shall he come in, sir? (征求对方意见)
二）用于二、三人称 表命令、许诺、警告、规定、威胁、决心、也用于宣布法律、规定的要求
1. You shall get my reply tomorrow. (许诺)
2. “The interest shall be divided into five parts, according to the agreement made by both side. （命令）
3. You shall be sorry for what you said one day, I tell you. (警告、威胁)
4. Nothing shall stop us from advancing. (决心)
5. —What does the sign over there read?
—“No person shall smoke or carry a lighted cigarette,cigar or pipe in this area.”(要求)
Should
一）应该,表示责任、义务
According to the air traffic rules, you should switch off your mobile phone before boarding.
二）竟然、（ 从句中） 惊奇、怀疑、不满(expect, think, believe等词后） 委婉 客气（第一人称 ） 惊讶、埋怨 （二、三人称） 万一（ if 从句中）
1.） it’s a pity that he should be so careless. (竟然)
2.） I never expect that you should have come here. (惊奇 )
3.） I should advise you not to do it. (委婉 客气)
4.） Who should come to see you when you are in trouble! (埋怨 )
5.）If you should change your mind, please let me know. (万一)x09
三） 表示合理的推测
The video should be very interesting, in which you can see foreigners making Jiaozi during the Spring Festival.
四）if 引导的虚拟条件句中,从句中只可出现should.
Should I have time, I would go there with you.
五）要求,命令和请求含义的动词后,接宾语从句,从句中谓语“should do”,should 可以省略
Tom suggested that I (should) go there at once.
六）should have done 本应该做但是没做
shouldn’t have done 本不应该做但是做了
You should have studied hard.
Must
一）表示必须要做的事: 必须
-Must I get to the station before three o'clock?
-Yes, you must. ( No, you needn't. )
二）用于指 偏要、硬要 （ 令人不快的事）
1. The car must break down just when we were in the jungle. (偏要)
2. -- Could I have a word with you, mum?
-- Oh, dear, if you must.
3. – Who is the girl standing over there?
-- Well, if you must know, her name is Mabel.
三）用于表肯定的猜测
He is absent today, and something must have happened to him.
She must be at home now, as I just called her.
四）禁止 (否定句)
You mustn’t make noises in the library. (禁止) (注：mustn’t没有表推测的意思)
Can could
一）x09能力（陈述句）He can swim./ He could swim when he was a child.
二）x09惊异、怀疑、不相信（否定、疑问、惊叹句）How can you be so careless?
三）x09can’t 表推测“一定不是” He can’t be Mr. White, because I don’t know him.
四）x09can/ could 用于否定和疑问表猜测 I lost my purse. Where could I have put it?
五）x09can 用于客观事实的推测,可能出现的某种现象
He is friendly, but sometimes he can be difficult to get along with.
The northern part of China is cold, but sometimes it can be warm.
Nowadays, graduates can have difficulty finding jobs.
六）x09be able to do sth. 经过努力能达到
4. The fire in the hotel spread fast but fortunately all of the people were able to ran out. (经过努力能达到)
May might
一）祝愿（祈使句） May you return in safety. (祝愿)
二）可以（语气弱）. May I come in ? (可以)
三）表推测,不太可能的推测 Helen may go on the trip with us, but she isn’t quite sure yet.
四）may as well do sth. Now that you are here, you may as well try your best.
may well do sth. He may not well go with us—he hates travel.
五）might用于虚拟 If he came here tomorrow, he might have a chance of talking with her.
Will
一）意愿、决心、习惯性、倾向性、请求
1. I’ll do my best . (意愿)
2. I will never do such a thing again. (决心)
3. Fish will die without water. (习惯性、倾向性)
4. Will you give me a piece of paper? (请求)
二）区分于be going to, 表示没有计划,临时决定
---I’m sorry. I forgot to send the letter for you.
--- It doesn’t matter. I will go myself.
Would He promised he would never smoke again. (will的过去式)
Would you…? “I would like to… (婉转语气)
Last year our English teacher would sometimes tell us stories in English after class.
(过去的习惯动作,比used to正式,并没有“现已无此习惯”的含义.)
It would be about ten when he left home. (表料想或猜想)
Dare need
1. I dare to go there alone at night.
2. Do you dare to go there alone at night? = Dare you go there alone at night?
3. I don’t dare (to )go there alone at night. = I dare not go there alone at night.
dare say dare tell dare speak
4 needn’t have done 本没有必要做,但是做了
You needn’t have waited for her, as she didn’t go there.
情态动词+ do 表示对现在的推测
情态动词+ have done 表示对过去的推测（对过去的一种结果的假设或虚拟）
(1)x09should (not) / ought (not) to have done本（不）应该做某事,但却没有做或做了,含有责备或后悔之意.
例如： —I’m sorry. I _________at you the other day. B
—Forget it. I was a bit out of control myself.
A. shouldn’t shoutx09x09x09x09x09 B. shouldn’t have shouted
C. mustn’t shoutx09x09x09x09x09x09C. mustn’t have shouted
(2) could have done本来能够做某事但未做.例如：
Thank you for all your hard work last week. I don’t think we ______ it without you. B
A. can managex09x09 B. could have managedx09
C. could manage D. can have managed
(3) needn’t have done本没有必要做某事但却做了.要注意needn’t do则表达“没有必要去做某事”,时间上应该是现在或将来.例如：
—Catherine, I have cleaned the room for you. B
—Thanks. You ________ it. I could manage it myself.
A. needn’t do B. needn’t have done
C. mustn’t do D. shouldn’t have done
(4)would (not) have done本来(不)会发生某事,但却（发生了）或没有发生.常用于虚拟条件句或含蓄虚拟条件引导的虚拟语气,表示对过去所发生事情结果的假设.例如：
He hesitated for a moment before kicking the ball, otherwise, he ________ a goal. D
A. had scored B. scored
C. would score D. would have scored
(5) might have done表示“本来可能……”,但实际上没有发生的事.例如：
What a pity! Considering his ability and experience, he ________ better. D
A. need have done B. must have done