仁爱版英语八年级上册情态动词讲解.ppt

情态动词,,定义：,情态动词具有情态意义，即它所表示的是说话人对动作的观点，如需要、可能、意愿、或怀疑等特征：,1.在形式上，情态动词不像实义动词那样有各种变化，只有could，would，had to，might等几个过去式其它如must，ought to等表示过去时形式不变 2.在意义上，大多数情态动词有几多个意义：如can表示“能够”，“可能”，“允许”等；may 可表示“可能”“允许”“目的”“让步”等 3.情态动词没有人称和数的变化，适用于各种人称 4.情态动词后加动词原形构成谓语部分can/could Can表示能力，许可，可能Could 是can 的过去式，表示过去的能力Could表示可能时，比can 所表示的可能性小，表示请求允许和许可时，可以代替can，意为“可以”，语气更为委婉2019/8/1,can的用法,1.表示能力如： We can carry the heavy box. 我们可以搬得动箱子 Who can sing an English song? 谁会唱英文歌？ 2.表示惊讶、不相信等态度，主要用于否定句和疑问句中猜测）如： Can it be true? 这会是真的吗？ You can't be serious? 你不会当真吧？ 3.表示允许，意思与may相近，主要用于口语中。

如： Can I smoke here? 我可以在这儿吸烟吗,2019/8/1,could,1) 提出委婉的请求，（注意在回答中不可用could） 例如： Could I have the television on? 我能看电视吗？ Yes, you can. / No, you can’t. 可以/不可以 (2)在否定句、疑问句中表示推测或怀疑例如： He couldn’t be a bad man. 他不大可能是坏人2019/8/1,,所有的can、could与be able to区别； 区别：can、could强调的是天生的能力；(与生俱来的) be able to表示设法做成某事；(通过后天的努力) can't + too +adj.表示再……也不过分 Eg: You can't be too careful when crossing the road. 译文：当你过马路的时候，再怎么小心也不过分,,may/might 1.表示可能但不肯定，通常用于肯定陈述句，暗含不确定而might 比may 的可能性小，更具有不确定性如： He may arrive tomorrow。

2.表示允许或征求同意，多用于肯定句和疑问句在提出请求时，might 比may 语气更委婉，更有礼貌 May I put here？ Might I use your phone？ 3.句型can/may/could/might I …?表示请求对方许可，其中can语气最不正式，could语气比较客气，委婉，may/might 用于正式场合，语气恭敬，might比may更为客气 肯定回答：of course，you can/may 否定回答：no，you can’t/may not(不用could或might),2019/8/1,,4.表示祝愿 May you happy everyday! 祝你开心每一天！,must,基本用法：,1.表义务，可用于肯定句和疑问句 You must take care of your parents. 2.must的否定式，表示不许，禁止，如： You mustn’t park here. 3.表示推测，暗含很大的可能或符合逻辑，只用于肯定句如： You must be hungry now The letter must be from her pen pal。

4.表示劝告，必须做某事，表明事情的必要性与重要性如： You must wear a coat 5.回答带must 的疑问句时，要用needn’t或don’t have to来作为否定回答，不能用，mustn’t如： Must we keep the window open all the time？ --- No，you don’t have to/No，you needn’t.,,Must 和 have to的区别 1.must 和have to都有必须的意思但是，must强调说话者主观的看法，而 have to 强调客观的需要例： I must leave now.（我想走） I have to cook for my grandfather(爷爷年纪大生病了等客观原因) 2.must 没有过去式，而had to 表示过去已实现的动作 I had to borrow some money at that time.,2019/8/1,shall,表示征询意见，用于第一人称的疑问句中 如： Shall we take you to the hospital? What shall we do this weekend?,2019/8/1,should“应该”学会使用 should作为情态动词用，常常表示意外、惊奇、不能理解等，有“竟会”的意思， 例如：How should I know? 我怎么知道？ Why should you be so late today? 你今天为什么来得这么晚？ should 常用来表示劝告、建议、认为某人“应该、应当”做某事，或“有责任和义务”做某事 1．用于表示“应该”或“不应该”的概念。

此时常指长辈教导或责备晚辈 例如：You should be here with clean hands. 你应该把手洗干净了再来 2. 用于提出意见劝导别人例如： You should go to the doctor if you feel ill. 如果你感觉不舒服，你最好去看医生2019/8/1,need,1.need作实义动词，意为“需要”如： need to do sth. eg. Do you need to stay at home?你要呆在家里吗？ 2.need作情态动词，一般用于对must的否定回答如： ---Must he leave now? 他必须离开吗？ ---No, he needn't. 不，他不必2019/8/1,3.区分：,a.need作实义动词 He needs to go. He doesn't need to go. Does he need to go? Yes, he does./No, he doesn't. b.need作情态动词，一般不用于肯定句 He needn't go. Need he go? Yes, he need./No, he needn't.,2019/8/1,,,2019/8/1,l练习,1—_____ I water the trees on Tuesday? —No, you needn’t. A. Can B. Must C. May D. Shall 2. —_____ I turn on the radio? —You’d better not. It is noisy enough in this room. A. Shall B. Must C. Need D. Do 3 Let’s go to the library this afternoon, _____? A. shall we B. will we C. can we D. should we 4. Everyone _____ do his best to make the world clean. A. can B. may C. should D. had to 5. _____ to have lunch with us today? A. Do you like B. Would you like C. Will you like D. Have you like,,,,,,,,2019/8/1,6 —Will you lend me your book? —Yes, I _____. A. will B. need C. can D. must 7. He _____ to the farm yesterday. A. need go B. needed go C. has to go D. had to go 8. You _____ to the meeting this morning if you have something important to do. A. needn’t to come B.don’t need come C.don’t need coming D.needn’t come,,,,2019/8/1,11 You _____ get down the bus until the bus has stopped. A. can’t B. needn’t C. mustn’t D. don’t 12. She looks so sad. She _____ ill. A. can be B. should be C. must be D. will be 13. I want to go to the hospital, but you _____ with me. A. need to not to go B. do not need go C. need not go D. need go not 14 Mary _____ be in London because I saw her in town just now. A. mustn’t B. isn’t able to C. may not Dcan not,,,,,2019/8/1,17 John___ come to see us tonight, but he isn't sure yet. A. may B. canC. has to D. must 18 They ___ do well in the exam. A. can be able to B. be able to C. can able to D. are able to 19-May I take this book out? -No, you___. A. can't B. may not C. needn't D. aren't 20 You___ go and see a doctor at once because you got a fever. A. can B. must C. dare D. would,,,,,2019/8/1,,21-Can you speak Japanese? -No, I____. A. mustn't B. can't C. needn't D. may not 22-He___ be in the classroom, I think. -No, he ___ be in the classroom. I saw him go home a minute ago. A. can; may not B. must; may not C. may; can't D. may; mustn't 23 -Shall I get one more cake for you, Dad? -Thanks, but you___, I had enough. A. may not B. must not C. can'。