3 Lack of obligation/necessity

Present/future

You needn’t come if you don’t want to.

You don’t have to do it now.

Past

They said it was quite near, so he didn’t need to take the car. (= it wasn’t necessary to take the car, and he didn’t)

When he got there he found it was quite near, so in fact he needn’t have taken the car. (= he took the car unnecessarily)

Note: With didn’t have to either meaning can be conveyed, depending on the stress and intonation used.

He didn’t have to go to London (but he did).

He didn’t have to go to London (but he didn’t).

Other expressions

She’s not obliged to go.

It’s not obligatory/compulsory.

It’s not (absolutely) necessary for you to go.

These classes are voluntary.

4 Advice

Present/future

You should/ought to ask for more money.

Past

You should/shouldn’t have gone there on your own.

Note: The perfect form expresses disapproval of something that was done.

Other expressions

I wouldn’t recommend you to go there.

It would be a good idea to tell him.

Customers are advised to retain their receipts.

It is advisable to book first.

If I were you, I’d do it.

It was wrong of him to borrow the money.

5 Opportunity/free choice

Present/future

You can take whatever you want.

You could always go tomorrow (if you wanted to)

Past

You could take whatever you want.

He could have been a doctor if he’d wanted.

Other expressions

It’s up to you whether you go or not.

It’s your decision/choice whether you stay or go.

He’s free to do whatever he wants.

You will have the opportunity to travel wherever you want.

6 Permission

Present/future

‘Could I borrow this book?’ ‘Of course you can!’

Past

They said I could go wherever I wanted.

Note: It is also possible to say May/Might I borrow this book? But this is rather formal and old-fashioned and

is not frequently used.

When talking about a particular occasion in the past, could is not possible.

I could/was allowed to drive my father’s car whenever I wanted.

On her tenth birthday, Lisa could/was allowed to ride her bicycle to school.

Other expressions:

He lets me go wherever I want.

The librarian gave me permission to take the book.

7 Ability

Present/future

Can you manage on your own?

Past

I could speak English when I was six.

Note: When talking about a particular occasion in the past, could not possible.

I could/was able to swim when I was very young. (general ability)

Although I was very frightened, I could/was able to tell the police officer what had happened. (particular event)

Other expressions:

After a lot of effort, I managed to do it.

I know how to swim.

She has the ability to sense the feelings of others. (formal)

She is capable of doing very well if she wants to.

Note:

1 need/need to

When need is used as a modal verb, it is followed by the bare infinitive. (This is most common in the negative form.) It removes obligation imposed by the speaker.

He needn’t come if he doesn’t want to.

When it is used as a main verb, it is followed by the full infinitive, and can refer to obligation from an external force.

He really needs to be careful.

It is often used in the question form.

Do we need to bring our own sheets and towels?

2 be supposed to/suppose

Compare:

You’re supposed to be working. (suggests criticism = You’re meant to be working – and you’re not.)

I suppose I’ll have to go. (express reluctance = I’m afraid I’ll have to go, even though I don’t want to.)

Modals and related expressions (2) (p.74)