Lesson3 Grammar
Tips：All things in their being are good for something.(天生我材必有用)
Learning aim: learn the use of the modal verbs have to /not have to , can/can’t, ought to /ought not to
Learning methods: observe----learn-----summarize------use
Learning steps:
StepI: Underline all the following words in the texts and translate them.
have to , don’t have to, ought to, ought not to, can’t,can
StepII: Match the verbs to their meanings.(A級(jí))
1 have to a) not necessary
2 don’t have to b) necessary
3 can c) not allowed/not possible
4 can’t d) allowed/ possible
5 ought to e) not advisable
6 ought not to f) advisable
StepIII:Transtrate the following sentences.(B級(jí))
1.1)I can’t go out now, I have to look after my baby .
______________________________________
2)I must find a job,my parents can’t support me any longer.
_____________________________________________
3)— Must we hand in our exercise books today?
— Yes, you must. (No, you don’t have to/need’t.)
________________________________________________
總結(jié)：must 和have to表示___________，但must表示___________觀，have to表示_________觀(如例句1，2所示)
讀一讀，記一記:
must與have to有下列幾點(diǎn)不同：
① must表示的是說(shuō)話人的主觀看法，而have to則往往強(qiáng)調(diào)客觀需要。
The play is not interesting. I really must go now.
I had to work when I was your age.
② must與have to 的時(shí)態(tài)差別： have有時(shí)態(tài)的變化,如三單has, 過(guò)去時(shí)had ,表示 客觀上的不得不，能與所有 時(shí)態(tài)一起。must為情態(tài)動(dòng)詞, 無(wú)時(shí)態(tài)的變化 , 表示主觀上的必須, 需要。
③ 二者的否定意義不大相同。如：
You mustn't go. 你可不要去。
You don't have to go. 你不必去。
④ 詢問(wèn)對(duì)方的意愿時(shí)應(yīng)用must。如：
Must I clean all the room?
2 1)Can you speak English?
__________________________________________________ can表示(如體力和腦力方面)，意為“__________”等can表示時(shí)，還可用be able to代替。如：
I'll not be able to come this afternoon.
2)表示請(qǐng)求或允許，多用在口語(yǔ)中，意為“__________”等。
— Can/Could I go now?
— Yes, you can.(回答語(yǔ)中不能用could)
3) 表示驚異、懷疑、不相信的態(tài)度。(主要用在否定句、疑問(wèn)句或驚嘆句中)
Can this be true? ______________________
How can you be so careless! ___________________
This cannot be done by him. __________________
4)在變否定句時(shí)，直接在后加上“not”,可縮寫(xiě)成_________或___________, 但不能寫(xiě)成cann’t。例如：
(變成否定句) He can swim. → _______________________
3 ought意思是______________后面跟帶有 to 的動(dòng)詞不定式否定式為_(kāi)________________。(C級(jí))
You ought to read these books if you want to know 高中政治 how to repair the motorcar.
____________________________________________
You ought to bring the child here.
_____________________________________________
You ought not to walk alone at night. _____________________________________________
注意： ought to和should的區(qū)別：
1.ought to語(yǔ)氣略強(qiáng)。 2.should較常用。
3.ought to在美國(guó)英語(yǔ)中用的很少，而should卻相當(dāng)常用。
4.ought to屬正式用語(yǔ)。
練一練：(C級(jí))
1The man in the office____________be Mr. Black because he went home
just now.
A. mustn’t B. may not C. can’t D. needn’t
2---Can you go surfing with us this afternoon?
----I’d like to , but I ________ look after my sister at home , because my mother is ill.
A. need B. must C. have to D. should
3----Can I take this book out of the reading room?
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