深圳牛津英语 7B unit 6 Grammar(情态动词)

1、7B unit 6 GrammarModal verbs,can and cannot may and may not must and must not,Modal verbs 情态动词,情态动词本身有一定的词义，但需要与动词原形一起使用，给谓语动词增添情态色彩，表示说话人对有关行为或事物的态度和看法，认为其可能、应该或必要等。 情态动词后面通常加动词原形。本单元我们要具体学习的是can,may 和 must 这三个情态动词。,2,Grammar: Modal verbs,I can spell all the words we have learnt. Can you do that?,Y

2、es, I can. No, I cannot/cant.,A can and cannot,can and cannot,我们用 can 表示某人具备某种能力做某事。此时可用 be able to 代替。如： I can play basketball.我会打篮球。 =I am able to play basketball. 当表示“经过努力才得以做成功某事”时应用be able to，不能用can。如： He was able to go to the party yesterday evening in spite of the heavy rain.,can 的过去式为 could,

3、could表示过去的能力.如：He could run ten years ago.十年前他还可以跑步。,can 的否定形式为cannot 或 cant.如： I cannot swim.我不会游泳。 疑问句中，把 can 提到句首，将 can 与主语的位置对调。 Can you speak any foreign languages? 你会说外语吗？ 肯定回答：Yes, I can. 否定回答：No, I cant.,Game time,What can you do? Tell the student behind you and ask if he/she can do it. The

4、next student should repeat this with another student.,Example:,No, I cant. I can sing. Can you sing?,Yes, I can. I can Can you ?,I can swim. Can you swim?,Grammar exercise,can,cannot,cannot,can,cannot,can,can,cannot,3,You will be given several situations. After reading the descriptions and looking a

5、t the pictures, decide what you would say in these situations.,a. A man is going to see his boss. He is standing at the doorway.,May I come in?,b. A student is going to ask the teacher a question.,May I ask you a question?,c. A boy is thirsty. He is asking his mother for something.,May I have some w

6、ater?,d. A shop assistant is serving a customer.,May I help you?,We use may and may not to ask for and give permission. In less formal situations, some people like to use can and cannot (cant) for the same purpose. “May” can be interchanged with “can”, but its a little more polite to use “may” .,B m

7、ay and may not,may and may not,在请求对方的许可，或是准许你做某事是，常用情态动词may 和 can。may (否定形式为 may not,没有缩写形式)比较正式，can 较常用且更口语化一些。 如： -May I leave work early today? -Yes, you may./ No, you may not. -Can I open a window? -Yes, you can./ No, you cant. You may/ can use my bike. You may not/ cannot use my computer.,Gramm

8、ar exercise,May/Can,May,can,May,Can,4,C must and must not,What do these signs mean?,（You mustnt smoke here.）,（You mustnt climb this ladder.）,（You mustnt swim here.）,（You mustnt use your mobile phone here.）,must and must not,must 用以表示“必须做某事”或“一定要做某事”，具有强制性，表达一种责任或义务或表示很有必要做某事；或在提出建议时使用，意为“应该，得”。 We m

9、ust obey the school rules. 我们必须遵守校纪校规。 The windows are very dirty. I must clean the 窗子很脏，我必须擦一擦了。 We must to to the bank today. We havent got any money. 我们今天一定要去银行了我们一点钱都没有了。,must 的否定形式为mustnt(= must not ),表示“禁止，绝不允许”，具有强制性如：Imust hurry.I mustnt be late.我必须要快点，我绝对不能迟到。You mustnt forget to phone Tom.

10、你绝对不能忘记给汤姆打电话。,must “必须” dont have to neednt do dont need to 2. must还可表示“偏偏、偏要” e.g. Must you make so much noise? 你偏要弄出这么多噪音吗？,1. 不必须,mustnt 禁止,I must go to bed early.,I must take the medicine on time.,eat cold food,I must not go out alone.,I must not share cups with others.,由must引出的一般疑问句，肯定回答用must,

11、否定答语用neednt 或 donthaveto。如：,MustIdotheworknow? 我必须现在干这个活吗？ Yes,youmust/haveto. -No,youneednt/donthaveto.,must be “肯定推测” e.g. - What is Tom? - He must be a student. “否定推测” cant be e.g. - Where is Tom? - He cant be in the library., 拓展 (推测,可能), He is in the classroom. 100% must 99% (must表推测，用于肯定句) e.g.

12、 He must be in the classroom. 他肯定在教室。 may 50% (may表推测，用于肯定句) e.g. He may be in the classroom. 他可能在教室。 cant / couldnt (can/could表推测用于否定句) e.g. He cant be in the classroom. 他不可能在教室。,must 必须 表示说话人的主观看法 have to 不得不 表示外界客观愿望，即“不得不”。 e.g. The headteacher gives us such an important work to do. We must do our best. e.g. My mother is calling me. I have to go.,拓展 （must 与