★ 思维导图
★语法：情态动词
一、情态动词的定义
情态动词是一类用于表示说话人的语气和情态的助动词。常表示命令、请求、拒绝、义务、可能、需要等。
二、情态动词的特点
1. 情态动词无人称和数的变化,
2. 情态动词后面跟的动词需用原形,否定式构成是在情态动词后面加 \。
3. 个别情态动词有过去式, 过去式用来表达更客气, 委婉的语气, 时态性不强, 可用于过去，现在。
三、情态动词的用法
1. can/could； can’t/couldn’t (否定)
1) 表示能力, 意为“能、会”, 例如： 如：I can speak a little English. -- Can you ride a bike? -- Yes, I can. / No, I can’t. I can’t swim. 2) 表示请求或允许，多用于口语中，意为“可以、能”等 如：You can go home now. 现在你可以回家了
-- Can I borrow your bike? -- Yes, you can. / No, you can’t. You can’t stop your car here.
3) 用于否定句、疑问句中，表示猜测、怀疑或不肯定.
如：Lucy can’t be at home now, she went to the park just now. Where can it be? I can’t find my football. 【注意：】
1） could 是can的过去式, 有两种用法, 一种表示过去式；一种用来表达更加客气, 委婉的语气, 时态性不强, 可用于过去，现在。 2） be able to 意为“有能力，能够做...”, 相当于can/could, 但它有人称，数和时态的变化。
2. may; may not (否定)
1) 表示“请求，许可”，此时与 can 同义，可以互换使用 如：May I borrow your bike?
Can I borrow your bike? Yes, you may. / No, you may not. Yes, you can. / No, you can’t.
2) may/might表示不太肯定的猜测，意为“有可能”
如：Lucy may come to school late today. It might rain today. 【注意】：
might 是may 的过去式, 有两种用法, 一种表示过去式，一种表示更加委婉, 客气的语气或对可能性的怀疑。
3. must; mustn’t (否定)
1) must(“必须”, 表示命令)，mustn’t(一定不能”, 表示强烈禁止...)
如：You must go to bed before 22:00pm. You mustn’t play with fire. It’s dangerous!
--Must I write down the sentences？ --No，you needn’t. (--No, you don’t have to) 注意：在回答must的疑问句中，否定回答用needn’t或don’t have to表示“不必”，不用mustn’t 2) must 还可以表示非常肯定的猜测，意为“一定” 如：The girl in a red skirt must be Lucy. 3) must/ have to 的区别：
①. must表示必须，强调主观上的愿望；have to表示“不得不”，强调客观需要 如：You must go be bed before 22:00pm.
My bike is broken, so I have to go to school on foot. ②. have to 有人称、数、时态的变化；must则没有。 如：I have to clean the classroom today. She has to finish her homework first.
It was late, he had to go to school without breakfast.
★巩固提升
一、用 must, mustn't, may, may not, can, can’t填空 1. __________ I come in?
2. I __________ speak a little French. 3. __________ I have a look at your pictures?
4.The child __________ ride a bike. He falls over all the time. 5. The red light is on. We __________ stop. 6. __________ she finish it in three hours?
7. I __________ drive a car, but I will lean to drive when I grow up.
8. You __________ borrow three books at a time. But you __________ keep one for a week.
9. The new law(法律) says drivers __________ rive after drinking wine.
10. --- __________ I finish the work today? --- No, you needn’t. 二、单项选择
1. This is just between you and me. You __________ tell anyone about this. A. mustn’t B. can C. may D. must
2. Don’t play with the knife, or you __________ get hurt. A. cannot B. must C. may D. may not
3. Sorry, I __________ tell you where she is. A. may B. may not C. can D. can’t 4. You __________ go and see a doctor at once because you’ve got a fever. A. can B. must C. may D. would 5. --- Are you going to Beijing by plane?
--- It's fast, but expensive. So I'm not sure. I __________ take a train. A. should B. must C. may D. could 6. --- You __________ smoke in the forest. --- Sorry, I won't do that again.
A. can B. may C. needn’t D. mustn't
7. --- __________I finish the homework today? --- No, you needn't. A. Must B. Can C. Should D. May
8. You __________ do it if you really don't want to. A. mustn't B. can’t C. needn't D. shouldn't 9. --- Must I return the book tomorrow morning?
--- No, you __________. You __________ keep it for three days. A. needn't; must B. mustn’t; must C. needn't; can D. mustn’t; may 10. --- May I take this book out? --- No, you __________. A. shouldn't B. may not C. needn't D. aren’t 三、完形填空
If we try to think of the most important inventions in the 20th century, I think electricity __1__ the most important, in a way. It plays an important part __2__ the development of the modern world. It can affect everyone’s life in one way or __3__. When the electricity __4__ off, we call it a power cut. Can you imagine __5__ our lives will be like __6__ electricity? Almost everything __7__. Electricity appliances __8__ work;
7B Unit6 Grammar 知识点练习-七年级英语牛津深圳版(广州沈阳通用)下册
