4_Obligation_notes

I n t e r m e d i a t e G r a m m a r Grammar reference Obligation modals FORM Positive and negative I You We They have to don’t have to must mustn’t go home. He She has to doesn’t have to Question Do I you we they have to go home? Does he she USE We use must and have to to talk about something that is necessary or important. The meaning is very similar, but 1. Must shows that the obligation comes from the person speaking. It is more personal. 2. Have to expresses a general obligation based on a law or rule, or on the authority of another person. It is more objective. 3. Must is more formal than have to; it is often written down, e.g. on public notices. Have got to is informal. 4. Must is used for strong recommendation. The negative forms mustn’t and don’t have to are completely different! 5. Mustn’t means something is wrong, dangerous or not allowed. 6. Don’t have to (= haven’t got to or don’t need to or needn't means something is not necessary. I n t e r m e d i a t e G r a m m a r EXAMPLES 1. I must try to eat more vegetables. Parent to teenage son: You must be home by eleven. 2. You have to drive on the left in Britain. I have to work on Saturdays. Teenager to friend: I have to be home by eleven. 3. Passengers must show their boarding cards. I’ve got to go now. See you! 4. You must read that book, it’s absolutely wonderful! 5. You mustn’t leave young children on their own. You mustn’t take aspirin with alcohol. We mustn’t walk on the grass. 6. You don’t have to wear a tie if you don’t want to. NOTES • Must has no tense forms. For obligation in the past we use had to. You’ll have to rise early if you want to go fishing. We had to wear a uniform in school. • Must I… is possible, but not common. • In spoken English, have to (UK have got to) is more common than must. I must /have to get up early