present and future Ability Certainty and uncertainty Obligation Explanations Can and be able to Can, like all modal verbs, cannot be used in an infinitive or continuous form. We use be able to in situations where we need these forms. I'd like to be able to swim. Not being able to swim is annoying. m Must and can't These words have a meaning related to certainty - they are used to make deductions. This is when we are sure or almost sure about something because it is logical. This usage is especially common with the verb be. You must be tired after your long journey. (I'm sure you are) That can't be Sue. She's in Brazil. (I'm sure it's not possible) These words are also used in other ways: must for obligation (see next section) and can('t) for ability (see above). ■ May, might and could These words all express uncertainty or possibility. Could is not used with not in this context. J might go out, I don't know. I could get wet! The meaning for all three words is approximately 50 per cent probability. But if we stress the modal verb strongly in speech the probability is reduced. / might see you later if I finish my work, but don't count on it. (might is strongly stressed in speech) ■ Should and ought to These words are both used for obligation (see next section). But they also have a meaning related to certainty - they are used when we expect that something will happen. Brenda should be home by now. (I expect that she is) ■ Be bound to This is used to say that something is certain to happen in the future. You're bound to see Paula if you go there. (I'm sure you will) ■ Must and have to In writing there is no real difference between these words. In speech there is sometimes a small difference. Must is used when the speaker personally feels something is important and have to is used when the situation makes something necessary. You must start working harder! (I say so) You have to turn left here. (it's the law) Sorry, I must leave/have to leave now. (in this example there is no difference) GRAMMAR 16 MODAL VERBS: PRESENT AND FUTURE i Mustn't and don't have to Be careful: must and have to are very similar in their affirmative forms (see previous paragraph) but they are completely different in their negative forms. Mustn't describes something which is prohibited. Don't have to describes something which is not necessary. You mustn't leave now. (It's not allowed. It's against the rules.) You don't have to leave now. (It's not necessary. You have a choice.) Should and ought to These words have the same meaning. They are used to say what is the best thing to do. They can be used to give an opinion, some advice, or polite instructions. We should do something different for our holidays this year. I think you should see a doctor. You ought not to smoke if you're pregnant. You should send in your application by Jidy 18th. Had better This phrase gives strong advice about how to stop something going wrong. It can refer to present or future time. J think you'd better leave now. (before it is too late) You'd better not drive. (it might be dangerous) Is/'Are to This is used in formal instmctions. Not is stressed. No-one is to leave the room. You are not to leave the room. 92 93 FIRST CERTIFICATE LANGUAGE PRACTICE GRAMMAR 16 MODAL VERBS: PRESENT AND FUTURE Practice Underline the correct word or phrase in each sentence. a) There's someone at the door. It can/must be the postman. b) Don't worry, you don't have to/mustn't pay now. c) I think you had better/would better take a pullover with you. d) Jones could/must be president if Smith has to resign. e) Sorry, I can't stay any longer. I have to/might go. f) It was 5 o'clock an hour ago. Your watch can't/mustn't be right. g) It's a school rule, all the pupils have to/must wear a uniform. h) I suppose that our team must/should win, but I'm not sure. i) Let's tell Diana. She could/might not know. j) In my opinion, the government might/should do something about this. 2 Complete the second sentence so that it has a similar meaning to the first sentence, using the word given. Do not change the word given. You must use between two and five words, including the word given. a) I think you should give up smoking immediately, had I think you ............................smoking immediately. b) I expect we will get there by 5.00, if there isn't too much traffic, should We............................................................5.00, if there isn't too much traffic. c) Is it necessary for me to bring my passport? have Do.................................................................................................my passport? d) I am sure that the cat is in the house somewhere, be The cat ......................................................................in the house somewhere. e) An aerial is not required with this radio, have You don't ...................................................................an aerial with this radio. f) It is very inconvenient if you can't drive, to It's very inconvenient if...........................................................................drive. g) I am sure that John is not the thief, be John ....................................................................................................the thief. h) I am certain that Norman will be late, bound Norman......................................................................................................late. i) All students should report to the main hall at 9.00. are All students ................................................................to the main hall at 9.00. j) I thought that you would know better! ought You..........................................................................................................better! Underline the most suitable word or phrase in each sentence. a) We can't be lost. It isn't allowed/I don't believe it. b) Jane is bound to be late. She always is/She must be. c) Late-comers are to report to the main office. It's a good idea/It's the rule. d) You don't have to stay unless it's necessary/if you don't want to. e) Astronauts must feel afraid sometimes. They're supposed to/It's only natural. f) You can't come in here. It isn't allowed/I don't believe it. g) All motorcyclists have to wear crash helmets. It's a good idea/It's the rule. h) I ought not to tell Jack. It's not a good idea/It's the rule. i) We should be there soon. / expect so/It's absolutely certain. j) You'd better leave now. That's my advice/That's an order! Complete each sentence so that it contains might, might not, must, mustn't, can or can't. More than one answer may be possible. a) Don't stand up in the boat! You.......Might.......fall in the river! b) Sue says she's stuck in traffic and she..........................be late. c) You really..........................start spending more time on your work. d) Tell Peter he..........................stay the night here if he wants to. e) That's a really stupid idea! You..........................be serious, surely! f) You..........................realise it, but this is very important to me. g) Don't be silly. You..........................expect me to believe you! h) We're not sure but we..........................go to Prague for Christmas this year. i) Me learn to fly! You..........................be joking! j) Bill cooked the lunch, so you..........................expect anything special! 94 95 FIRST CERTIFICATE LANGUAGE PRACTICE GRAMMAR 16 MODAL VERBS: PRESENT AND FUTURE 5 Rewrite each sentence so that it contains can, could, must, have to or should (including negative forms). c) a) I'm sure that Helen feels really lonely. b) You're not allowed to park here. c) It would be a good idea if Harry took a holiday. d) I'm sure that Brenda isn't over thirty. ;) Do I need a different driving licence for a motorbike? f) What would you advise me to do? g) Mary knows how to stand on her head. h) You needn't come with me if you don't want to. i) It's possible for anyone to break into this house! j) The dentist will see you soon. I don't think he'll be long. 6 Choose the most suitable description for each picture. a) b) 1) He should be exhausted! 2^1 He must be exhausted! 1) We mustn't pay to go in. 2) We don't have to pay to go in. d) e) f) 1) I'm afraid we have to operate. 2) I'm afraid we should operate. 1) Mind out, you could drop it! 2) Mind out! You can drop it! 1) Thanks, but I'd better not! 2) I don't have to, thanks. 1) We must be here for hours! 2) We're bound to be here for hours! Key points 1 Most modal auxiliaries have more than one meaning. You should think carefully about the context, or tone of voice, to understand the meaning. 2 The negative forms mustn't and don't have to have different meanings. You mustn't go. (it's against the rules) You don't have to go. (it isn't necessary) 3 In normal speech should is a weaker obligation than must and have to. You should go to the doctor. (I think it's a good idea) You must go to the doctor, (it's necessary) But in formal speech or writing shoidd can be a way of expressing a strong obligation. Passengers for Gatwick Airport should change at Reading. SEE ALSO Grammar 17: Modal verbs: past Grammar 20: Consolidation 4 96 97