Unit 31. Have to and must.

Unit 31; Part A

I have to do something = it is necessary to do it, I am obliged to do it:

•    You can't turn right here. You have to turn left.
•    I have to wear glasses for reading.
•    George can't come out with us this evening. He has to work late.
•    Last week Tina broke her arm and had to go to hospital.
•    I haven't had to go to the doctor for ages.

We use do/does/did in questions and negative sentences (for the present and past simple):
•    What do I have to do to get a new driving licence? (not What have I to do?)
•    Karen doesn't have to work Saturdays. (not Karen hasn't to)
•    Why did you have to leave early?

You can use have to with will and might/may:
•    If the pain gets worse, you'll have to go to the doctor.
•    I might have to work late tomorrow evening. or   I may have to work ...
     (= it's possible that I will have to)

Unit 31; Part B

Must is similar to have to:

•    It's later than I thought. I must go. or   I have to go.

You can use must to give your own opinion (for example, to say what you think is necessary, or to recommend someone to do something). Have to is also possible:
•    I haven't spoken to Sue for ages. I must phone her. (= I say this is necessary)
•    Mark is a really nice person. You must meet him. (I recommend this)

We use have to (not must) to say what someone is obliged to do. The speaker is not giving his/her own opinion:
•    I have to work from 8.30 to 5.30 every day. (a fact, not an opinion)
•    Jane has to travel a lot for her work.

But must is often used in written rules and instructions:
•    Applications for the job must be received by 18 May.
•    (exam instruction) You must write your answers in ink.

You cannot use must to talk about the past:
•    We had to leave early. (not we must)

Unit 31; Part C

Mustn't and don't have to are completely different:

*You mustn't do something* = it is necessary that you do not do it (so don't do it):	*You don't have to do something* = you don't need to do it (but you can if you want):
*• You must keep it a secret. You mustn't tell anyone.* (= don't tell anyone)	*• You don't have to tell him, but you can if you want to.*
*• I promised I would be on time. I mustn't be late.* (= I must be on time)	*• I don't have to be at the meeting, but I think I'll go anyway.*

Unit 31; Part D

You can use have got to instead of have to. So you can say:

• I've got to work tomorrow. or I have to work tomorrow.
• When has Liz got to go? or When does Liz have to go?

Exercises

1 Complete the sentences with have to / has to / had to

Complete the sentences with have to / has to / had to.

1    Bill starts work at 5 a.m.    He has to get up at four. (he / get up)
2    'I broke my arm last week."   'Did you have to go   to hospital?' (you / go)
3    There was a lot of noise from the street. ________________ the window. (we / close)
4    Karen can't stay for the whole meeting. ________________ early. (she / leave)
5    How old ________________ to drive in your country? (you / be)
6    I don't have much time ________________.(I / hurry)
7    How is Paul enjoying his new job? ________________ a lot? (he / travel)
8    'I'm afraid I can't stay long.'    "What time ________________?' (you /go)
9    'The bus was late again."    "How long ________________ ?' (you / wait)
10 There was nobody to help me. I ________________ everything by myself. (I / do)

2 Complete the sentences using have to + the verbs in the list.

Complete the sentences using have to + the verbs in the list. Somesentences are positive (I have to ... etc.) and some are negative (Idon't have to ... etc.):

ask do drive ~~get up~~ go make make pay ~~show~~

1    I'm not working tomorrow, so I    don't have to get up    eariy.
2    Steve didn't know how to use the computer, so I    had to show    him.
3    Excuse me a moment - I ________________ a phone call. I won't be long.
4    I'm not so busy. I have a few things to do, but I ________________ them now.
5    I couldn't find the street I wanted. I ________________ somebody for directions.
6    The car park is free. You ________________ to park your car there.
7    A man was injured in the accident, but he ________________ to hospital because it wasn't serious.
8    Sue has a senior position in the company. She ________________ important decisions.
9    When Patrick starts his new job next month, he ________________ 50 miles to work every day.

3 Correct the sentences where necessary.

In some of these sentences, must is wrong or unnatural. Correct the sentences where necessary.

1    It's later than I thought. I must go.
2    I must work even- day from 8.30 to 5.30 .
3    You must come and see us again soon.
4    Tom can't meet us tomorrow. He must work.
5    I must work late yesterday evening.
6    I must get up early tomorrow. I have lots to do.
7    Julia wears glasses. She must wear glasses
      since she was very young.

OK (have to is also correct.)
I have to work
___________________________
___________________________
___________________________
___________________________

___________________________

4 Complete the sentences.

Complete the sentences with mustn't or don't/doesn't have to.

1    I don't want anyone to know about our plan. You    mustn't tell anyone.
2    Richard    doesn't have to    wear a suit to work, but he usually does.
3    I can stay in bed tomorrow morning because I ________________ go to work.
4    Whatever you do, you ________________ touch that switch. It's very dangerous.
5    There's a lift in the building, so we ________________ climb the stairs.
6    You ________________ forget what I told you. It's very important.
7    Sue ________________ get up early, but she usually does.
8    Don't make so much noise. We ________________ wake the children.
9    I ________________ eat too much. I'm supposed to be on a diet.
10 You ________________ be a good player to enjoy a game of tennis.

Unit 30 Unit 31 Unit 32