(
课件网) 新人教必修Book 3 Unit 5 The Value of Money Discovering Useful Structures P54 Leading-in May we ask what you're doing in this country and what your plans are I can't say that I have any plans. You mustn't worry about that. Could you offer me work here Read the sentences below and think about: What are the functions and meanings of these modal verbs 情态动词没有人称和数的变化，即不随主语的不同而变化。 They must be in the classroom. 情态动词不能独立使用，须后接动词原形，一起构成谓语动词。 The little boy can read and write. 情态动词没有非谓语形式，即没有不定式、分词等形式，后加动词原形。 People who are familiar with the game will know this. 否定结构为：情态动词＋not。 The young man can’t carry the big stone. 一、情态动词的特点 Modal verbs have many functions as follows: A. necessity B. possibility C. obligation D. request E. advice F. intention 二、情态动词的功能 必要性 可能性 职责/义务 请求 建议 意图和愿望 You have to read between the lines because the real messages are often hidden… It may seem lucky to you. Astronauts must wear spacesuits when they work in space because… May we ask what you’re doing in this country You should/ought to/had better go to class right away. What would you do if you were in her situation necessity 表必要性 possibility 表可能和推测 obligation 表义务性 request 表请求 advice 表建议 intention 表意图和愿望 A. necessity B. possibility C. obligation D. request E. advice F. intention 2. must 表示必须、必要。回答must引出的问句时, 如果是否定的 回答, 不能用mustn’t，而要用needn’t 或 don’t have to。 三、情态动词的用法 must, have to — Must we hand in our exercise books today — Yes, you must. (No, you needn’t\don’t have to.) 1. must 表示推测时， 只能用于肯定句。 There must be something wrong with the computer. 3.have to和must均表示“_____”，但_____是指说话人的主观看法，而_____则强调客观需要。。 ① I must recite the text this morning. ②I have to wait here because I have no umbrella. have to 必须 must can/could 1. can /could 表推测, 只能用在否定句或疑问句中。“可能” It’s so late. Can Tom be reading \ She couldn’t be telling lies. 2. can /could 表能力，can表示现在的能力，could表示过去的能力。“能够” I can read this chinese article. She could play the piano at the age of five. *can表示能力时，还可以用be able to代替。 be able to后接动词原形，可用于大多数时态。 3. can /could 表许可，could语气更委婉。“可以” Can I come in Could I borrow your pen may/might 1. 表示推测时, 只能用于肯定句, 可以指现在,也可以指过去，且可能性不大。 They may come here tomorrow. He might be doing his homework now. 2. 表示请求或允许, might可以指过去的时间，也可指现在的时间。 对may的一般疑问句的肯定回答可用may或can, 但作否定回答时要用mustn't或can't。 —May (Might) I have a little brandy —No, you mustn't. You'd better not. 3. May可以用于祈使句，表示祝愿或希望，而might不行。 May they be very happy in the future. May you succeed in the coming year. shall/should 1. 在一、三人称的疑问句中, s ... ...
