Unit1 period3 grammar高中M3.ppt

1、情態(tài)動詞用法,Words like can, will, may, must, and a few others are called modals. Modal auxiliary verbs help other verbs express a meaning or an idea. Some common uses of the modals are these: Ability: 1 He can speak English now. 2 He couldnt speak English a year ago. 3 Im not able to come to the game on

2、Friday.,Permission: All passengers may now board. We can board now. Obligation: You must fasten your seat belts. (strong) You should pay attention. (weak) You out to pay attention. Possibility: 1 It may rain. 2 How could I forget an import thing like that? 3 He cant /must have known the result.,Mean

3、ings similar to those of the modals can often be conveyed by real verb forms: He has to.=must is able tospeak English =can is allowed to.=may is supposed to=should,情態(tài)動詞的語法特征,1）情態(tài)動詞不能單獨(dú)做謂語，除ought 和have外，后面只能接不帶to的不定式。,2）情態(tài)動詞沒有人稱，數(shù)的變化，但有些情態(tài)動詞，如can、will也有一般式和過去式的變化。,情態(tài)動詞的語法特征,3）情態(tài)動詞的“時態(tài)”形式并不是時間區(qū)別的主要標(biāo)志，

4、不少情況下，情態(tài)動詞的現(xiàn)在式形式和過去式形式都可用來表示現(xiàn)在時間、過去時間和將來時間。,1) can的主要用法是： A. 表示體力或腦力的能力： eg. The girl can dance very well. B. 表示說話的推測事物的可能性等： eg. Can the news be true? C. 在口語中, can可以表示請求或允許: eg. Can I sit here?,can 和could：,2) could的主要用法是： A. could 是can的過去式, 表示與過去 有關(guān)的能力和推測: eg. We all knew that the young man couldnt

5、 be a doctor. B. could可以代替can表示請求, 但語氣較can客氣、委婉:,eg. Could you lend me your dictionary? Could I use your bike? 3) can和could接動詞的完成形式，表示可能已經(jīng)做某事。can用在否定和疑問句中, 表示不相信、懷疑等態(tài)度。 eg. They cant have gone out because the light is still on.,may 常用來表示： A. 表示請求、允許; 比can較為正式: eg. May I come in ? You may go now. B.

6、表示說話人的猜測: “也許” “可能”: 通常只用于肯定句和否定句中。,may 和might,eg. -I believe the man is from England. -But I may be wrong. The guest may arrive this afternoon. 在肯定句中，may 的可能性比can 高，may 表示現(xiàn)實(shí)的可能性，can 表示理論上的可能性。如：,The road may be blocked. 這條路可能不通了。 The road can be blocked. 這條路可能會是不通的。 在疑問句中，表示可能性用can。 如：Where can he

7、be? 他會在哪呢？,C. 表示祝愿;但語氣較正式: eg. May you succeed! May you have a good journey! might 的用法有: 多在間接引語中表示過去的可能和允許。如: She said that he might take her bike. 她說他可以拿她的自行車去用。,除了在間接引語中以外，might 一般不表示過去的可能或者許可。如要表示過去的可能可以用could, 表示過去的許可可以用was( were) allowed to 或者 had permission to 。 表示現(xiàn)在的可能，其可能性要比 may 小。如：,She mig

8、ht go home tomorrow. 說不定他明天會回家。 表示現(xiàn)在的許可，語氣比may 較委婉， 一般用于疑問句（包括間接疑問句）， 不可用于肯定句或者否定句。 如: Might I have a word with you? 我可以和你說句話嗎？,will和would：,1. will是助動詞還是情態(tài)動詞？ will用于構(gòu)成將來時是助動詞。 用于表示“意志”“決心”“請求”是情態(tài)動詞。would亦同理。 eg. I will tell you something important. 我要告訴你一些重要的事。 （助動詞）,Will you tell her that Im here?

9、請您告訴她說我在這兒，好嗎？ （情態(tài)動詞） 2. 在疑問句中用于第二人稱，提出請求或詢問。 eg: If you want help - let me know, will you? 如果你需要幫助, 讓我知道, 好嗎?,Will you type this, please? 請打印這個，好嗎？ Wont you sit down? 請坐下，好嗎？ 3. would比will客氣委婉。 eg: Would you help us, please? 請您幫助我們，好嗎？,（表請求）,Id go there with you. 我要和你一塊到那兒去。 Teacher wouldnt allow i

10、t. 老師不會允許這件事。,（表意愿）,（表許可）,shall和should：,1. shall用于構(gòu)成將來時是助動詞。 shall用于征求對方的意見， 表示 “決心” 是情態(tài)動詞。 eg: Perhaps I shall pay a visit to England this winter. 可能今年冬天我會去英國觀光。 （構(gòu)成一般將來時, 助動詞）,Shall we go by train, Mom? 媽媽，我們乘火車去好嗎？ （用于征求對方的意見，情態(tài)動詞） I shall go at once. 我必須立即去。 （表 “決心”，情態(tài)動詞）,2. should表示義務(wù)、建議、勸告，意為

11、“應(yīng)該”。 “should+ have+過去分詞” 表示本應(yīng)該在過去做但沒有做。 eg: You should keep your promise. 你應(yīng)該遵守諾言。 She should have passed the exam. 她應(yīng)該通過考試的。,must 的主要用法：,1. 表示必然性。 eg: We must all die. 人總要死的。 2. 表示強(qiáng)制或者義務(wù)。 eg: You must get up early. 你必須早起來。,注意: must not 的意思是不許可，不應(yīng)該或者禁止。 如：We mustnt waste our time. - May I take this

12、 magazine out? - No, you mustnt. must 用于一般疑問句的時候，肯定回答應(yīng)該用yes, please 或者 Im afraid so, 其否定回答應(yīng)該用 neednt 或者 dont have to。如：,表示推測，語氣非?？隙?，近乎確定的意味，一般用在肯定句。 如：It must be eleven oclock now. He must be crazy. 在表示推測的否定或者疑問句中必須用 can, 不可以用 must。,If Mary didnt leave here until five oclock, she cant be home yet. 如

13、果瑪麗五點(diǎn)才離開這兒，他此時一定還未到家。,1. A: _ you like to go to a special event with us on Saturday? B: Yes, I _ _.,Would,d like to go with you on,Saturday,Exercise,2. A: _ I go with my friend to the harvest festival? B: Yes, you _ _.,3. A: If I want to be a doctor _ I study science? B: Yes, you _.,should study sci

14、ence,May,may go ( with your,should,friends ),5. A: He is very handsome. _ he play the role of the prince? B: No, he_ _.,cant play the role of the,Can,prince,-_ I go out to play, mum? -No, you_. You should do your homework first. A. Might; wouldnt B. May; had better not C. Must; mustnt D. Need; mustn

15、t,B,2. -Where is Emma? -I cant say for sure where she is, but she_ be out shopping. A. can B. should C. must D. may,D,3. The room is in a terrible mess; it _ cleaned. A. cant have been B. couldnt be C. may have been D. would be,A,4. There _ be any difficulty about passing the road test since you hav

16、e practised a lot in the driving school. A. mustnt B. shant C. shouldnt D. neednt,C,1 Children under 12 years of age in that country _ be under adult supervision when in a public library. (2004 上海） A must B may C can D need,高考鏈接,2 Whats the name？ A Khulaifi. _ I spell that for you？（2006 北京） A Might

17、B Would C Can D Shall,3 Some aspects a pilots job_ be boring， and pilots often _ work at inconvenient hour. （2006 湖南） A can；have to B may；can C have to; may D ought to; must,4 You cant imagine that a well-behaved gentleman _ be so rude to a lady. (2001 上海） A might B need C should D would,5 The weath

18、er turned out to be fine yesterday. I the trouble to carry my umbrella with me. (2006 江西） A should have taken B could have taken C neednt have taken D mustnt have taken,6 Hows your tour around the North Lake? Is it beautiful? It _ be, but it is now heavily polluted. （2007 全國I） A. will B. would C. should D. m