1、Modal verbsRead the sentences aloud He can finish the 100 meter race in 11 seconds. You must work hard to win the gold medal. Can I have a look at your watch? Shall we do some exercises this morning? I will help you wash your dirty clothes. You shouldnt eat too much before sleeping.基本概念 （一）情态动词的定义 情
2、态动词表示说话人对某一动作或状态的态度。 （二）情态动词的特点 1）有一定词义；2）不受主语人称和数的变化影响；3）与主要动词的原形（或称不带 to的不定式）一起构成谓语（除 ought to作固定词组看待）。 三）情态动词的基本用法 1. can (could) 1）表示能力， could主要指过去时间。Nobody can stop the development of science.2）表示请求和允许-Can/Could I have a look at your new pen?-Yes, you can.3）表惊异、怀疑、不相信等态度。主要用于否定句、疑问句或感叹句中。这可能是真的
3、吗？你怎么能如此粗心？他不可能六十多岁了。Can this be true? How can you be so careless? He cant (couldnt) be over sixty. 4) can 用在肯定句中表示 理论上的可能性 (一时的可能 )。A house in the center of London can cost a lot of money.冬天有时暖和。It can be warm in winter.can 和 be able to 1）情态动词 can只有两种时态形式，现在式 can和过去式 could, 而 be able to有多种时态形式。 Mar
4、y can play the piano. She has been able to play it since she was 5.2)表示成功地做了某事时，只能用 was/were able toThe fire spread through the hotel, but everyone was able to get out.船翻掉的时候，他游到了岸上。When the boat sank he was able to swim to the bank .你再仔细都不过分。她只得同意我的观点。那个女孩忍不住哭起来。我非常感谢你。那部电影不能更糟了。我大笑起来，我就是忍不住。can或 c
5、ould 的否定形式构成习惯短语cant.too./ cant .enough.再 .也不过分cant(help)but do不得不做，只好做cant help doing 情不自禁cant help it 没有办法cant .+比较级 再 .不过了（表示最高级）I burst out laughing; I couldnt help it.You cant be too careful.She couldnt but agree to my idea.The girl couldnt help crying.I cant thank you enough.The film couldnt b
6、e any worse.2. may (might)1）表请求和允许， might可以指过去时间，也可指现在时间，语气更委婉。You may take whatever you like.-May I use your dictionary?-Yes, please. / Certainly./ Please dont .Youd better not. / No, you mustnt.She may not know about it.2）表 推测， 可能（事实上）。 might可能性小 (肯定， 不用于疑问句 )May you succeed. 3） 用于祈使句 ,表示祝愿 , 结构 may sb. doI wish I could go sightseeing this summerholiday, _?may I may well 很可能may/might as well 最好，不妨祝你成功！3. must 1）表示必须，必要（主观意志）。We must do everything step by step.-Must we hand in our exercise-books now?-No, you neednt. / No, you dont have to.- Yes, you must.have to 强调客观需要
