1、Page1 of 5小学英语教案情态动词情态动词本身有各种意义，但不能单独作谓语，只能和主要动词一起构成谓语，表示说话人的语气和情态，这样的动词称为情态动词。情态动词没有人称和数的变化。常用的情态动词有 can, could, may, might, will, would, should, must, need, dare 等。一、can, could 的用法1. can 的用法（1）表示能力、许可、可能性。如：Can you speak English? 你会讲英语吗？Can you play the piano? 你会弹钢琴吗？She can swim fast, but I cant.
2、 她能游得快，但我不能。I can see with my eyes. 我用眼睛看。（2）表示请求或者许可。如：Can I help you? 我能帮助你吗？You cant play basketball. 你不能玩篮球。Can you.？“ 请你好吗？” 表示说话人的请求；Can I.？“我可以吗？”用来征求对方是否允许自己做某事。如在句末加上 please 一词就显得更有礼貌了。例如：Can you help me, please? 请你帮助我好吗？You can use my dictionary. 你可以用我的字典。（3）表示推测，意为“可能”，常用与否定句和疑问句中，此时 cant
3、 译为“不可能”。如：Can the news be true? 这个消息会是真的吗？The moon cant always be full. 月亮不可能常圆。2. could 的用法（1）can 的过去式，意为“能、会”，表示过去的能力、可能性或允许：如：He could write poems when he was 10. 他十岁时就会写诗。I could run faster then.那时我能跑得更快。It could be no better at that time.那时好得不能再好了。（2）在疑问句中，表示委婉的语气，此时 could 没有过去的意思。如：Could you
4、do me a favour? 你能帮我个忙吗？二、may, might 的用法Page2 of 51. 都表请求或允许，might 可以指过去时间，也可指现在时间，语气更委婉。如：You may take whatever you like. 你喜欢什么就拿什么。May (Might) I ask for a photo of your baby? 我可以要一张你宝宝的照片吗？May I come in？我可以进来吗？在回答以 may 引起的问句时，多避免用这个词，而用其它方式，如 Yes, please. / Certainly. / Please dont ./ Youd better
5、not. / No, you mustnt.等，以免显得太严峻或不客气。2，表示可能。I may be busy tomorrow. 我明天可能会比较忙。Exercise 1. -Is John coming by train? -He should, but he _ not. He likes driving his car.A. must B. can C. need D. may2. Peter _ come with us tonight, but he isnt very sure yet.A. must B. can C. may D. will3. I thought you
6、_ be hungry, so I have brought you some cakes.A. may B. might C. can D. could三、must, have to 的用法1. 两词都是“必须” 的意思，have to 表示客观的需要，must 表示说话人主观上的看法，即主观上的必要。如：My brother was very ill, so I had to call the doctor in the middle of the night. 我弟弟病得很厉害，我只得半夜里把医生请来。(客观上需要做这件事)He said that they must work hard
7、. 他说他们必须努力工作。 （主观上要做这件事）2. have to 有人称、数、时态的变化，而 must 只有一种形式。如：He had to look after his sister at home yesterday. 昨天他不得不在家照看妹妹。3. 在否定结构中：dont have to 表示“不必”mustnt 表示“禁止”，如：You dont have to tell him about it. 你不一定要把此事告诉他。You mustnt tell him about it. 你一定不要把这件事告诉他。Must I finish the homework right now?
8、我现在必须完成家庭作业吗？Page3 of 5Yes, you must. / Yes, you have to. 是的。(No, you neednt. / No, you dont have to. 不，不必。)4. must be+表语，表示推测，它的否定和疑问形式用 can 代替 must。如：This must be your pen. 这个一定是你的钢笔。Your sister must be a doctor in this hospital. 你姐姐一定是这家医院的医生。Exercise 1. Come on! We _ hurry because there isnt muc
9、h time left.A. may B. must C. can D. need2. Amy did best in the English test. She _ hard last week.A. must have been working B. should have worked C. should work D. must work.四、should 的用法（1）用来提供帮助、提出建议，要求对方给出意见。如：Should I help you with the community affairs? 我可以帮你做一些社区事务吗？Should we clean the classro
10、om now? 现在我们可以打扫教室吗？（2）表达义务、职责等。如：I think todays children should really learn to respect their elders. 我认为今天的孩子应该好好学习尊敬长辈。You should （= ought to ） tell your mother about it at once. 你应该立即把此事告诉你妈妈。He should work harder. 他应该更加努力。You should help your mother with the housework. 你应该帮你母亲做家务。例. Look out! T
11、he knife is very sharp. You _ cut your finger.A. need B. must C. should D. may五、will, would 的用法1. 表示“将、将要、自愿做”等。如：People will die without air or water. 人离开水和空气将会死的。I will do my best. 我将会尽力而为。2. would like； Would like to do = want to 想要，为固定搭配。Page4 of 5如：Would you like to go with me? 你想和我一起走吗？3. Will
12、 you? Would you like? 表示肯定含义的请求劝说时，疑问句中一般用 some, 而不是 any。如：Would you like some cake? 你想要一些蛋糕吗？Exercise 51. _ I know your name?A. May B. Will C. Shall D. Must2. What kinds of homes will we live in the future? Nobody _ be sure, but scientists are working out new ideas now.A. will B. may C. can D. must
13、六、had better 的用法表示“最好”，相当于一个助动词，只有一种形式，后面要跟动词原形，否定词形式为 had better not。如：It is pretty cold. Youd better put on my coat. 天很冷，你最好把我的大衣穿上。You had better go now 你最好现在就走Hed(=He had) better do it now 他最好现在做Shed better not cry 她最好别哭例. You _ your tooth pulled out before it rot completely.A. had better got B. had to get better C. had better to get D. had better getPage5 of 5
