MODALS( THEORY)

M O D A L     V E R BS (BRENDA WADLEY)

1. CAN / COULD / BE ABLE TO:

We use "can" to say that something is possible or that someone has the ability to do something. The negative form is "can't".

You can see the sea from our hotel window.

Can you speak any foreign languages?

"Can" has only two forms - present and past (could), so BE ABLE TO is used in other tenses:

I haven't been able to sleep well recently. (pres.perf.)

"Could" is also used to express the general ability to do something:

When Tom was 13, he could run 100 metres in 11 seconds.

But if we want to say that somehting was done in one particular situation (with the sense of "managed to"), we use "was able to":

The fire spread through the building quickly, but fortunately everyone was able to escape.(=managed to)

Compare:

Jack was as excellent player. He could beat anybody.

(= he had the ability to...)

But on one occasion he played against Robert, who was

also very good. However, in the end, Jack was able to beat him.

2. COULD with future/present meaning:

When we make suggestions referring to the present or possible future, we use "could":

What shall we do this evening? - We could go to the cinema.

When you go to New York you could stay with Linda.

It is sometimes used to talk about possible future happenings:

There could be another rise in the price of petrol soon. (=it is possible there will be....)

3. COULD HAVE (DONE):

This is the past of "could" and is used to mean that we had the ability or opportunity to do something but did not do it:

We didn't go out last night. We could have gone to the cinema, but we decided to stay at home.

It also means that something was a possibility but didn't happen:

He was lucky when he fell off the ladder. He could have seriously hurt himself. (= but he didn't)

4. MUST / CAN'T = DEDUCTIONS:

We use "must" to say that we are sure that something is true:

You've been travelling all day; you must be tired.

(= I'm sure that you are...)

and "can't" to say that we think something is impossible:

You've just had dinner; you can't be hungry again.

(= it's impossible..)

For deductions in the past we use :

5. MUST HAVE / CAN'T HAVE (DONE):

The phone rang but you didn't hear it. You must have been asleep.

She passed me in the street without speaking. She can't have seen me.

6. MAY / MIGHT (HAVE):

We use "may" and "might" to say that something is possible. The only very small difference is that "might" often suggests less probability than "may", but usually they are interchangeable.

If you are looking for Jack, look in the office. He may be there (=it is possible that he's there)

The negative form is "may not" or "might not" (mightn't)

Possibility in the past is expressed by "may/might have":

I can't find my bag anywhere! - You might have left it in the last shop we entered.

Why didn't Ann come to the meeting? - She may not have known about it.

7. MAY / MIGHT = POSSIBILITY IN THE FUTURE:

These verbs are also used to express possible happenings or possible actions in the future:

I'm not sure where to go for my holidays, but I may go to Italy. (= perhaps I'll go....)

The weather forecast isn't very bright; it might rain this afternoon.

When talking about future plans, we express possibility, not certainty, with the continous form:

I might be going to Italy in July. (=it's possible, but not sure)

8. CAN / COULD = REQUESTS:

We use these when we ask someone to do something for us:

Can you wait a moment, please?

Ann, could you do me a favour?

Do you think you could lend me some money?

9. CAN / COULD / MAY = PERMISSION:

Used to ask for and give permission:

Could I use your telephone? - Yes, of course you can.

May I come in?

You can smoke in here, if you lke.

"Could" is never used to give permission.

10. MUST (DO) / HAVE TO (DO) = OBLIGATION OR NECESSITY:

We use "must" and "have to" to say that it is necessary to do something.

Oh dear! It's very late; I have to go now/I must

go now.

With "Must" the writer is giving his own feelings, saying what he thinks is necessary:

I must write to Ann; I haven't written for ages.

With "have to" the writer is giving facts:

Ann's eyes are not very good; she has to wear glasses.

"must" is only used to talk about present and future, whereas "have to" may be used in all tenses:

I had to go to hospital.

I might have to go to hospital. (infinitive)

11. MUSTN'T / DON'T HAVE TO = PROHIBITION AND LACK OF NECESSITY:

"mustn't" implies prohibition; it is necessary that you do not do something:

You mustn't tell anyone what I said. (= don't tell)

But "don't have to" means that is is not necessary to do it; you don't need to do something:

I don't have to wear a suit to work, but I usually do.

She stayed in bed this morning because she didn't

have to do to work. (it wasn't necessary ....)

12. NEEDN'T HAVE / DIDN'T NEED = LACK OF NECESSITY IN THE PAST:

We use "needn't have" to say that s.o. did something but it wasn't necessary (but he/she didn't know this at the time):

Ann bought some eggs, but when she got home she found that she already had some in the fridge - she needn't have bought any.

"Didn't need to" or "didn't have to" is different; it means that the action was unnecessary, and this was known at the time of carrying it out:

I didn't need to go, so I didn't.

I didn't need to go, but I decided to go anyway.

13. SHOULD = ADVICE:

We often use "should" when we say that we think something is a good thing to do or the right thing to do.

The film was great; you should go and see it.

The government should do something about the economy.

Should we invite Sue to the party? - Yes, I think we should.

In the negative form it means that it is not a good thing to do:

You shouldn't smoke so much.

"Should" is not as strong as "must":

You should stop smoking (= it would be a good idea)

You must stop smoking (= it's necessary for you to

stop)

For the past, we use "should have"/"shouldn't have":

The party was great. You should have come. Why

didn't you?

Why were you at home yesterday? You should have been at work.

She shouldn't have been listening to our conversation - it was private.

This form suggests that somebody did something wrong, and would have been better doing the opposite.

14. SHOULD - FUTURE SENSE:

It is used to say that something will probably happen:

I don't think I'll be late home; I should be home at the usual time.

She's been studying very hard, so she ought to pass her exams.

EXERCISE. COMPLETE WITH APPROPRIATE MODAL VERBS:

a) I ......... stay in bed tomorrow morning because I ...........work.

b) Whatever you do, you ............... touch that switch; it's very dangerous.

c) We ...................leave yet. We've got plenty of time.

d) You ........... forget what I told you. It's important.

e) Does Jack shave? - No, he's got a beard. He .............

.............. to.

f) Where's Janet? - I can't see her; she ...............gone out.