C. Modal verbs 1. Must - Obligation, necessity, duty - Prohibition - Strong advice - Logical assumptions o Must can only be used to talk about the present or near future. We use have to when we need to use other tenses. | C. Modal verbs 1. Must - Obligation, necessity, duty - Prohibition - Strong advice - Logical assumptions o Must can only be used to talk about the present or near future. We use have to when we need to use other tenses. 2. Must – have to/have got to - Must = it is necessary to do something (we use must when the speaker decides that something is necessary) - Have to = it is necessary to do something (we use have to when someone else decides that something is necessary) - Must and have to have different meanings n questions - Have got to has the same meaning as have to, and it is usually used in everyday speech. 3. Mustn’t – needn’t/ don’t have to - Mustn’t = it is forbidden to do something/ you are not allowed to do something. (prohibition) - Needn’t = it isn’t necessary to do something (the lack of necessity) (= don’t have to) 4. Didn’t need to – needn’t have done = lack of necessity - didn’t need to + infinitive = it was not necessary to do something, the action did not happen in the past because we knew it was not necessary. - Needn’t have + . = it was not necessary to do something, but it was done. 5. Can/ could - ability in the present: can = am/is/are able to - ability in the past: could = was/were able to - Asking permission: can/could I ? = Would you mind if ? - Giving/ refusing permission o Can/may = you are allowed to do o Can’t/ mustn’t/ may not = you are not allowed to do - Possibility o Could/may/might + infinitive = it is possible/ it is likely/ perhaps o Could/may/might + have + . = it was possible, but it didn’t happen. - Can is used in the present, could is the past tense of can. We use be able to to form all the other tenses 6. May/ might - possibility (present/ future) = could - asking permission - request 7. Should/ ought to - advice - criticism: ought to/should + perfect infinitive = it would have been better if you had (we use these structures to show that someone did the wrong thing in the past) Exercise 7: Fill in these sentences with appropriate modal verbs 1. You your homework before you watch TV. 2. I come in? It’s rather cold out here. 3. You water the plants this weekend, they look dry. 4. you collect the children from school, please? 5. you play the piano? 6. I buy some milk. There isn’t any left. 7. When I call you? 8. I swim before I was able to walk. 9. You walk to school. I’ll give you a lift. 10. Tim be out. There are no lights on.
