Obligation and necessity (1): must, have to, have got to

Must and have to

We use both must and have to to express obligation or necessity, but there is sometimes a difference between them:

We normally use must when	We normally use have to when the
the authority comes from the	authority comes from outside
speaker.	the speaker.
Mother: You must be home	Daughter: I have to be home
by 10 o'clock. (I insist.)	by 10 o'clock. (My parents insist.)
I've got a terrible pain in my	I have to go and see the doctor
back. I must go and see the	at 9.00 tomorrow morning. (I have
doctor. (I think it is neces-	got an appointment.)
sary.)
You must drive care-	You have to drive on the left
fully. (I insist.)	in Britain. (That is the law.)

We tend to prefer must:

— when we refer to ourselves (with I/we): I really must weed this garden.

— With you to express urgency: You must phone home at once.

— in public notices, etc.: Cyclists must dismount.

— (= Can't you stop yourself?): Must you interrupt?

— pressing invitations or advice: You must come and see us. You must repair that fence.

We only use must (+infinitive) to talk about the present and the future. When we talk about past obligation or necessity, we use had to.

I had to work late yesterday.

Must has no infinitive, -ing form or participles. So, when necessary, we make these forms with have to.

I'll have to work late tomorrow.

He hates having to get up early.

She's had to work hard all her life.

Note that in questions and negatives with have to we use do/does in the present simple and did in the past simple.

What time do you have to start work?

We don't have to hurry. We've got plenty of

time.

Did you have to walk home last night?

Have got to

We often use have got to instead of have to to talk about obligation and necessity. Have got to is more informal and is used primarily in spoken English. Have to is used in both formal and informal English.

I have to hurry. Do you have to go?

I've got to hurry. Have you got to go?

We normally use have to, not have got to, for things that happen repeatedly, especially when we use one-word adverbs of frequency eg always, often. Compare:

I always have to work late on Wednesday evenings. Do you have to get up early'

I've got to work late this evening. ? Have you got to get up early tomorrow?

We use got mostly in the present. To talk about the past, we normally use had to, not had got to.

I had to work late last night.

Activities

I. (i) Mrs Woods isn't very well. The doctor is speaking to her. Complete what the doctor says using must and the verbs drink, take, stay and continue. Use each verb only once.

Doctor: Well, Mrs Woods, your temperature is a little high, so you ... in bed for the next few days. You can eat whatever you like, but you ... plenty of liquids. And I'll give you some medicine. You ... it three times a day after meals. And you ... to take it for the next ten days.

(ii) Now Mrs Woods is explaining the doctor's instructions to Mr Woods. Complete what Mrs Woods says using have to and the verbs drink, take, stay and continue. Use each verb only once.

Mrs Woods: The doctor gave me some medicine. I ... it three times a day after meals. And I ... to take it for the next ten days. I'm not allowed to get up at the moment. I ... in bed for the next few days. Oh, and I'm allowed to eat whatever I like, but I ... plenty of liquids.

//. Complete the sentences using must or a form of have to. Sometimes two answers are possible.

1. I couldn't go to the party last night because I ... babysit for my sister. 2.1... get up early tomorrow morning. 3. You ... get a visa to visit the United States. 4. It's getting late. We ... go now. 5. I ... stay in bed yesterday because I wasn't very well. 6. Mr Mason ... wear glasses since he was a child. 7.1 don't like ... work at weekends. 8. He ... try harder if he wants to win the prize. 9. Notice in a picture gallery: Cameras, sticks and umbrellas ... be left at the desk. 10.1... do all the typing at my office. 11. You ... read this book. It's really excellent. 12. The children ... play in the streets till their mothers get home from work. 13. She felt ill and ... leave

early. 14. Mr Pitt ... cook his own meals. His wife is away. 15.1 hadn't enough money and I... pay by cheque. 16.1 never remember his address; I always ... look it up. 17. Employer: You ... come to work in time. 18. If you go to a dentist with a private practice you... pay him quite a lot of money. 19. Father to small son: You ... do what Mummy says. 20. My neigh­bour's child ... practise the piano for three hours a day. 21. Doctor: I can't come now. Caller: You ... come; he's terribly ill. 22. English children ... stay at school till the age of 16. 23. Notice above petrol pump: All engines ... be switched off. 24. Mother to daughter: You ... come in earlier at night. 25. The shops here don't deliver. We ... carry everything home ourselves. 26. The buses were all full; I ... get a taxi. 27. Notice beside escalators: Dogs and push chairs ... be carried. 28. Tell her that she ... be here by six. I insist on it. 29. Park notice: All dogs ... be kept on leads. 30. She ... learn how to drive when her local station is closed. 31. Railway notice: Passengers ... cross the line by the footbridge. 32. I got lost and ... ask a policeman the way. 33. If you buy that television set you ... buy a license for it. 34. When I changed my job I ... move to another flat. 35. Father to son: I can't support you any longer; you ... earn your own living from now on. 36. Whenever the dog wants to go out I ... get up and open the door.

III. Make questions with have to.

Example 'Tom had to go to the police station.'

'Why__________________________________?'

'Why did he have to go to the police station?'

1. 'Ann has to leave tomorrow.'

'What time exactly______________________________?'

2. 'We had to answer a lot of questions at the examination.' 'How many questions_____________________________?'

3. 'George had to pay a parking fine.'

'How much_____________________________________?'

4. 'He will have to work hard next month.'

'Why__________________________________________?'

5. 'We had to get up early to catch the bus.'

'What time_____________________________________?'

6. 'My mother has to go abroad a lot.'

'How often_________________________________ ?'

7. 'I have to leave tomorrow morning.'

'What time_____________________________________?'

8. 'We had to wait for ages.'

'How long______________________________________?'

9. 'I have to take my car to the garage.'

'Why________________________________________?'

10. 'Peter had to stay in bed for a week.'

'Why__________________________________ ?'

11. 'She'll have to go by bus.',

'Why_________________________________________?'

12. 'We have to dine out.'

'Why_________________________________________?'

IV. Make up short dialogues.

A: About this parcel — do we have to tie it up? B: Oh, yes, it must be tied up.

About ... — do we have to ...

1. these books ... take them back?

2. these old newspapers ... throw them away?

3. this broken glass ... sweep it up?

4. this wallet we've found ... hand it in?

5. these old curtains ... take them down?

6. the carpet ... roll it up?

7. this watch we are giving him ... wrap it up?

8. this information ... pass it on?

9. this notice ... put it up?

10. the instructions ... write them down?

11. these forms ... fill them up?

12. the money ... pay it back?

13. the dishes ... wash them up?

14. his orders ... carry them out?

15. the wall that you say is unsafe ... pull it down?

16. the documents ... lock them up?

17. the meeting ... put it off?

V. Say 'why'.

Examples: Jane is going - food/money/wine

to the bank.

She has got to go to the bank because she needs some money.

I am going to the shop, dress/glass of

water/money

I have got to go to the shop because I need a dress.