Exercise 9. Rewrite the following sentences as positive, negative or a question according to the instructions.

Date: 2015-10-07; view: 443.

Obligation and necessity: must/have to/need (to)

Exercise 8. Choose the best answer A or B.

Example: You A be late for classes.

A) are not allowed to; B) can't.

1. Mary's children watch the film on TV last night.

A) could; B) were allowed to.

2. try this on?

A) Am I allowed to; B) Can I.

3. Until the 19th century, people travel freely between most countries without a passport.

A) may; B) could.

4. In Britain you drive a car until you are seventeen.

A) cannot; B) couldn't.

5. In Russia you vote at the age of eighteen.

A) aren't allowed to; B) are allowed to.

6. I'm afraid, they to attend the meeting next week.

A) may not; B) will not be allowed.

MUST is used:

1) to express total obligation (the authority comes from the speaker)

I really must get a driving license.

Must we pay extra?

You must be home by 10 o'clock.

2) to express necessity

You must phone home at once.

I've got a terrible pain in my back. I mustgo and see the doctor.

3) to express prohibition

You mustn't be late for classes.

4) in public notices, etc.

All visitors mustreport to the duty officer.

Example: We mustn't tell him about the accident. (positive)

We must tell him about the accident.

I must fix the switch myself. (negative)

I mustn't fix the switch myself.

We must take part in the discussion. (question)

Must we take part in the discussion?

1. If a traffic light is red, a car mustn't stop. (positive)

2. He must work overtime every day. (negative)

3. You mustn't be at the airport an hour and a half before the departure of the plane. (positive)

4. You must wear a helmet when you drive a motorbike. (question)

5. Children must play with matches. (negative)

HAVE (GOT) TO is used:

1) to express obligation (the authority comes from outside the speaker)

I've (got) to be home by 10 o'clock. (My parents insist.)

We have to drive on the left in Britain. (That is the law.)

2) to express necessity

I have (got) to go and see the doctor at 9 o'clock.

NOTE:

a) Have to is not a modal verb but it often has the same meaning as must, and is used instead of must in some tenses. It forms questions and negatives in the same way as all other main verbs. We use do/does in the present, did/didn't in the past and will in the future.

I/You/We/They don't have to hurry. There's plenty of time.

He /Shedoesn't have to wear smart clothes to work.

What time didyouhave to start work yesterday?

Does he have to attend the meeting?

Jack will have to buy a new car soon.

It's Sunday tomorrow so I won't have to go to the institute.

b) We normally usehave to not have got to, for things that happen repeatedly, especially with adverbs of frequency.

I alwayshave to work late on Wednesday evenings.

I've got towork late this evening.

Do you often have to get up early?

Have you got to get up early tomorrow?

c) We often use have got to instead of have to to talk about obligation and necessity.

Have got to is more informal.

Have got is mostly used in the present.

I've got to stop smoking.

They had to go to Kiev for a conference.