专项：情态动词一 考点： 情态动词的用法和辨析, 情态动词表示推测和可能, 由情态动词引导的一般疑问句的回答二 类型 ：1 只是情态动词： can, could, may, might, must2 可做情态动词,可做实义动词： need, dare3 可做情态动词,可做助动词： will, would, shall, should4 特殊：have to, ought to, used to三 特征 ：1 有一定的词义,但不能单独作谓语,必须与行为动词和系动词连用组成谓语2 无人称和数的变化 （have to 除外）Eg: He has to stay here.3 后接动词原形4 具有助动词作用,可组成否定,疑问或简短回答四 用法：1. can① 表示能力, “能,会 ”Eg : Can you play basketball?② 表示怀疑,猜测,常用于否定句或疑问句Eg :Li hua can b e’int the classroom.③ 表示请求,允许,多用于口语,译 “可以”=may.Eg: you can go now.④can 开头的疑问句,肯定句,否定句用 can或 can’t.2.could ①can 的过去式,表示过去的能力。
Eg :I could swim when I was seven years old.②could 开头的疑问句,肯定和否定回答用 could, couldn ’t 如果 could表示现在的委婉,用 can 回答Eg: Could I have a drink? Yes, you can.3.may ① 表示推测, “可能,也许 ”,用于肯定句Eg: He may come tomorrow.② 表示请求, “许可,可以”Eg: May I borrow your book?注：表示请求,许可时,主语为第一人称的一般疑问句,否定回1 答用 mustn’不t “可以,禁止,不许 ”不, 用 may not“可能不 ”③表示祝愿 Eg :May you success.4 .might ①表示 “可以 ”,用于过去时中Eg: He told me I might smoke in the room.②用于现在时,表示说话更委婉,礼貌Eg:He might be doing his lessons now.5 .must①表示 “必须,应该 ”②表示推测,常用在肯定句中,表 “一定 ”Eg:There is someone knocking at the door.It must be Jim.③否定句中, mustn’t 表示禁止,“不允许”。
④以 must 开头的疑问句, 肯定句回答用 must,否定回答用 needn’t , 表示“不需要,不必” =“don’t have to”.⑤表示“偏偏”Eg: Must you play the piano at this time.6 .need ①情态动词： +do,用 need 提问或回答,肯定句回答用 must ,否定句回答用 needn’t. Eg: You needn’t come to school so early.②实义动词： +to do ,用助动词提问和否定③+doing 表示被动④needn’t have done 表示没必要做某事但是做了Eg: I actually needn’t have bought so much wine.7 .dare ①情态动词,多用于疑问句,否定句,条件句中Eg: I m’afraid you dare not to do such a thing.注：I dare say 习惯说成“也许,我想” Eg: It will rain this afternoon, I dare say.②实义动词：dare to do ,用于肯定句中, 当用于否定句或疑问句时, to 可以省略。
Eg: This student doesn’t dare to raise any question in class.8 .shall ①用于第一人称表示征求意见,询问Eg: Shall I open the window?Shall we have lunch here?②表示说话人的态度, “命令,警告,允诺,威胁” Eg: You shall finish your homework first.2 ③用于第三人称, 在条约, 规定, 法令等文件中表示义务或规定, “应该,必须”不常用）9 .should ①表示义务,责任“应该” Eg:We should obey traffic laws.②作为 shall 过去式,用于第一三人称,表示征求意见 Eg:Mr leeasked if he should get his visa.③表示“竟然”Eg: It’s unthinkable that the boy should sing such a beautiful song.④表示说话人的特殊情感,如惊奇,愤怒,失望等Eg: How should I know?⑤表示劝告,建议, “应该”。
Eg: You should listen to your teacher.10.will ①用于第二人称表示询问, 请求,也可以表达现在的 “意愿”Eg: Will youpass me the book?②表示意愿,决定,允诺,用于各种人称Eg: I will try my best to help you.③表示规律性的“注定会” Eg: People will die without air or water.11.would ①表示过去的意愿或委婉询问Eg: Would you tell me the way to the station?12.have to①“必须,不得不”,强调客观需要,含有时态的变化Eg: I ’ll have to ask Jim instead.②区别：must 表示“必须,应该“,主观看法13.ought to ①表示职责, 义务或要求, 及人们应该去做的正确的事或好事 Eg:Humans ought to stop polluting nature.②比 should 语气强, ought to 反映客观情况, should 表示主观看法③ought to have done本应该做而没有做。
Eg: You are late. You ought to have arrived five minutes earlier.14.used to①表示“过去常常,过去是“,没有人称和数的变化,可以和过去的3 时间状语连用否定形式： usedn’t to 或didn’t use to 疑, 问词将use提前或 Did⋯use to⋯?Eg: He didn’t use to be so careless.②区别 would :带有主观性,并且现在做不做不知道 Used to :客观性,和现在进行对比,过去常常,现在就不怎么做了Eg: He would phone me on Sunday.Eg: I used to be very fond of music when I was young.③区别：be used to doing（情态动词）习惯于 ⋯Used to do （情态动词）过去是,过去常常 ⋯Be used to do (过去式) 被用来做 ⋯Eg: I am already used to noisy city life here.My parents used to live in South America.This machine is used to cut up waste paper.15.其他 ：⑴had better do 最好做某事 Eg: You had better stay at home.否定：had better not do⑵be able to 与 can 表示能力时用法相同,但前者有时态的变化,有能力成功做某事。
Eg: We will be able to come back next week.专题练习 ：1( ) 1 John___ come to see us tonight, but he isn't very sure yet.A. may B. can C. has to D. must( ) 2 They ___ do well in the exam.A. can be able to B. be able to C. can able to D. are able to( ) 3 -May I take this book out?-No, you___. A. can't B. may not C. needn't D. aren’t( ) 4 You___ go and see a doctor at once because you're got a fever.A. can B. must C. dare D. would( ) 5 -Can you speak Japanese?-No, I____. A. mustn't B. can't C. needn't D. may not4 -Thanks, ___. A. I will B. I won't C. lean D. I may -No, you mustn't. You____read it only here.A. Must; can B. May; can C. Need; must D. Must; must7( ) 1 Excuse me. ___ you please pass me that cup?A. Do B. Should C. Would D. Must( ) 2 ___ you like to have another try?A. Could B. Will C. Would D. Do( ) 3 -Would you like to go boating with us?-Yes, ___.A. I'd like B. I want C. I'd like to D. I do8( ) 1 You___ worry about your son. He will get well soon.A. needn't B. can't C. mustn't D. have to( ) 2 The poor man needs our help, ___ he?A. need B. needn't C. does D. doesn't( ) 3 -Must we do our homework first?-No, you___. You may have a rest first.A. mustn't B. needn't C. may not D. can't6科教兴国6。