Permission- Obligation- Necessity Docx 136l3l

Permission, obligation and necessity

CAN / MUST / SHOULD / OUGHT TO / HAD BETTER The most common modal verbs for talking about permission and obligation are can / could, must, and should / ought to. 1.

I couldn't take any photos in the museum.

2.

engers on the bus mustn't distract the driver.

3.

We should go home on the motorway – it's much quicker.

4.

We ought to go home on the motorway – it's much quicker.

We can use should have or ought to have + past participle to talk about past events which did not happen and which we regret. 5. We should have gone home on the motorway – it would have been quicker. 6. We ought to have gone home on the motorway – it would have been quicker.

Had better is stronger and more urgent than should / ought to and is often used to give strong advice or a warning. It normally refers to the immediate future. The negative is had better not NOT hadn't better . 7.

You'd better post the parcels today or they won't get there in time.

HAVE TO / HAVE GOT TO We also use have to to express obligations. It can be used in any tense. 1.

All engers will have to fill in an immigration form on arrival.

2.

You don't have to tip unless you think the service was excellent.

We can also use have got to to express obligation, but it is normally used for specific occasions rather than repeated or general obligations. 3.

I've got to buy a birthday present for my sister Daniela.

NEED We use need / don't need + to + infinitive to say that something is necessary or unnecessary. You can use these forms for habitual, general, and specific necessity. 1.

You usually need to check in two hours before a flight leaves.

2.

I don't need to take a jacket. It's going to be hot today.

When we want to say that something is unnecessary on a specific occasion, we can also use needn't + bare infinitive (without to).

We use don't need to (NOT needn't) for habitual or general necessity, e.g. Marie doesn't need to wear glasses. Her eyesight is still good. NOT Marie needn't wear glasses . 3.

You needn't lock the car. Nobody will steal it in this village.

When something was not necessary, but you did it, we can use needn't have + past participle or didn't need to + infinitive. 4.

We needn't have booked a table. The restaurant is empty!

5.

We didn't need to book a table. The restaurant is empty!

When something was not necessary, so you did not do it, you must use didn't need to (you cannot use needn't have to). Pay attention: NOT We had plenty of petrol so we needn't have stopped . 6.

We had plenty of petrol so we didn't need to stop.

BE ABLE TO / BE ALLOWED TO / BE SUPPOSED TO We often use be able to or be allowed to + infinitive to talk about what is possible or permitted instead of can, particularly when we want to use a form which can does not have. 1.

From tomorrow we won't be able to park in this street.

2.

You are not allowed to smoke in any public buildings in Argentina.

Be permitted to + infinitive is used in formal situations, e.g. notices and announcements, to say what can / can't be done according to the law or to rules and regulations.

IMPORTANT: We do not use the subject it followed by be allowed to: NOT It isn't allowed to take mobiles into the exam room . 3.

It is not permitted to take mobiles into the exam room.

We can also use be supposed to + infinitive to say what people should or shouldn't do, often because of rules. There is often a suggestion that the rules are not necessarily obeyed, e.g. Students are not supposed to have guests after 12.00, but everyone does. 4.

We are supposed to check in at 3.30. What's the time now?

5.

You aren't supposed to park here – it's a hospital entrance.

On the next page you will be able to practise this grammar.

PRACTICE Permission, obligation and necessity ACTIVITY 158: Choose from the menus the modal verb that is NOT possible in the following sentences. Then check the correct answers. 1. We check out before 12 or the hotel will charge us for another night.

2. When we were children, we stay out late.

3. I packed some warmer clothes - I'm freezing!

4. You drop litter here, but many people do.

5. Some of my family attend our wedding. It was held abroad.

6. I study tonight because my exams are over.

7. We look in on your mother this weekend. She hasn't been well.

8. We ring the bell because the door was open.

9. You see a doctor about that cough.

Permission, obligation and necessity ACTIVITY 159: Complete the second sentence so that it means the same as the first using the words in blue capitals. Then check the correct answers.

1. It is compulsory for motorcyclists to wear a helmet. TO You on a motorbike.

2. We regret buying such a big house. SHOULDN'T We such a big house.

3. I couldn't wear jeans to work in my previous job. ALLOWED I jeans to work in my previous job.

4. The sign says 'Don't walk on the grass', but nobody takes any notice. AREN'T You on the grass, but nobody takes any notice.

5. Please turn off your laptop. It might interfere with the flight instruments. BETTER You your laptop. It might interfere with the instruments.

6. Camping is strictly prohibited in most national parks. AREN'T You in most national parks.

7. The best thing to do would be to apply for a transfer to a different department. TO You really for a transfer to a different department.

8. We took sandwiches, but they weren't necessary. TAKEN We sandwiches.

9. You can't use mobile phones in this carriage. NOT The use of mobile phones in this carriage.