1、Function and Grammar,Function: Talking about obligation or lack of obligation,a. You must arrive on time at a party.You have to arrive on time at a party. Which of the following is true? a) They both indicate an obligation. b) They are only suggestions about what to do. c) The first one is an obliga
2、tion, the second one is a suggestion.,1,b. You mustnt take yellow flowers for the host. You dont have to take yellow flowers for the host.,Which of the following is true? a) They mean the same thing. b) The first one is an obligation, the second one indicates a lack of obligation. c) The first one i
3、ndicates that something is against the law.,c. You dont have to take a gift. You dont need to take a gift.,Which of the following is true?a) They mean the same thing.b) The first one is an obligation, the second one isnt.c) The second one is an obligation, the first one isnt.,What is “obligation” ?
4、It is a noun, meaning 1. a moral or legal duty or tie. 2. the binding power of such a duty or tie. 3. a debt of gratitude for a service.,Talking about obligation or lack of obligation,100% necessity: You must leave straight away. You have (got) to leave straight away. must v. have (got) to Generally
5、, must shows what the speaker feels and it is the speakers authority; have (got) to is when the speaker uses an external force which they cannot control. doctor to patient: Youve got to stop smoking. patient to themselves: I must stop smoking.,0% necessity: We dont have to pay to get in. We have not
6、 got to see the boss after all. We neednt stay late. These have an element of being optional, i.e. We neednt stay late but we can if we want to.,obligation: You ought to call your mother. You should call your mother. These show that calling your mother is the right thing to do. There is no real diff
7、erence between ought to and should, but ought to is perhaps a little stronger. We use neednt to show an action is optional - I can do it if I want to. We use mustnt to say an action is forbidden - I have no choice.,1 We all know each other. We dont need to worry about small talk. This means _. it is
8、nt necessary to worry about it unfortunately we worry about it 2 The party is informal. You neednt wear a tie. This means _. we must not wear a tie we can wear a tie if we choose,a,b,3,Stop! You _ give yellow flowers to the host! Its unlucky! Dont worry. You _ eat anything you dont like. 3. Im sorry
9、, you cant leave. You _ wait until the prizes have been given.,mustnt/cant/shouldnt,dont have to/neednt,4,must/have to,4. _ I _ take some food to the party? 5. You _ take a gift to the host, but she will be very pleased if you do.,Do have to/need to,dont have to/dont need to,If you go to a social ev
10、ent in my country, 1 you have to _. 2 you dont have to _. 3 you mustnt _.,2,Work together,1. In crowded places like airports and railway stations, you_ take care of your luggage. (2017 北京)A. can B. may C. must D. will 2. The boss has given everyone a special holiday, so we go to work tomorrow. (2018
11、 上海春)A. cant B. mustnt C. neednt D. shouldnt,高考链接,3. -What do you think we can do for our aged parents?-You _ do anything except to be with them and be yourself. (2017重庆) A. dont have to B. oughtnt to C. mustnt D. cant,Grammar: didnt need to do neednt have done,You neednt have spoken so slowly. Who
12、said this the tourist or the English person? Why did she say it? Choose one of these possible reasons. The other person was speaking too quickly. The other person was speaking too slowly. The other person was speaking slowly and it wasnt necessary.,1,the tourist,Read the sentence and decide which en
13、dings are possible.,I didnt need to buy a gift for my host family _.a) because I already had oneb) so I didnt get onec) so I bought oned) so I took it back and got a refund,3,Rewrite these sentences using neednt have done.,It wasnt necessary for you to bring some flowers!You neednt have brought some
14、 flowers. Thank you for tidying the room but it wasnt necessary.You neednt have tidied the room.,2,There was no need for you to buy the box of chocolates.You neednt have bought the box of chocolates. Why did you go to school? Its Sunday!You neednt have gone to school. Its Sunday! Thank you for bring
15、ing the book to show me, but I already have it.You neednt have brought the book to show me. I already have it.,Complete the sentences using didnt need to or neednt have done.,We brought some food to the party but there was too much, so we _ (bring) any. My friend spoke good Mandarin so I (translate)
16、 _ the speech for him.,neednt have brought,didnt need to translate,4,3. The office had already opened when we arrived so we _ (wait) outside in the street. 4. I got to the party at 6 p.m. but there was no one there, so I _ (arrive) so early. 5. I told the host all about my home town and then he told
17、 me hed been there. I _ (tell) him anything!,didnt need to wait,neednt have arrived,neednt have told,高考链接,The weather turned out to be fine yesterday. I _ the trouble to carry my umbrella with me. (2016江西) should have taken B. could have taken C. neednt have taken D. mustnt have taken,2. As you work
18、ed late yesterday, you_ have come this morning. (2016陕西) A. maynt B. cant C. mustnt D. neednt 3.-I dont mind telling you what I know.-You .Im not asking you for it. (2017江苏)A. mustnt B. may not C. cant D. neednt,高考链接,翻译句子,1. 在英国，车辆必须靠左行驶。 In England traffic must keep to the left. 2. 冬天的时候，我们得穿温暖的衣服。 We have to put on warm clothing in winter. 3. 在这么短的旅程中，你实在没有必要多买油。 You need not have bought extra oil for this short trip.,Thank you!,
