Obligation and advice, Lack of obligation or necessity, Asking for and giving permission

Obligation and advice: should and ought to, be supposed to

We use ought to and should to talk about obligations and duties in the future, present and past, or to give advice

– You ought to/should speak English in class.
Shouldn’t we tell someone about the accident?
Oughtn’t we to have invited Mandy?

We can use be supposed to when saying what someone should or should not do according to rules or regulations

– You‘re not supposed to park here.

Should + have + past participle is often used to criticise your own or other people’s behaviour

– I should have told you before.
– You shouldn’t have promised that.

Other phrases for advice

It is advisable/wise to keep documents in a safe place.
– You should remember that…
– Travellers are reminded that banks close on Saturdays.
– Guests are recommended to keep documents in a safe place.

Obligation and advice, Lack of obligation necessity, Asking for and giving permission

Lack of obligation or necessity

We use needn’t, don’t need to, don’t have to to talk about a lack of obligation, in the present or future

– You don’t need to/needn’t meet me at the station.
– We don’t have to wait. We can go straight in.

We use needn’t + have + past participle to say that somebody did something, but that it was unnecessary

– You needn’t have gone to all that trouble.

We use didn’t need to + infinitive to say that something wasn’t necessary without saying whether the person did it or not

– You didn’t need to bring any extra money.

Asking for and giving permission

We can use to ask for and give permission

Can I borrow your calculator for a few minutes.
– Yes, you can stay up and watch the late night film.
– You can’t wait here. It’s private. (= not allowed to)

We use could to ask for permission when we are not sure what the answer will be

Could I open the window?  Yes, of coure you can.

Watch Out! could is not used for giving permission.

We use may to ask for or give permission in formal situations

May I take that chair?
– You may use pen or pencil.


Obligation and advice, Lack of obligation or necessity, Asking for and giving permission publicat: 2017-12-18T18:57:23+00:00, actualizat: 2017-12-18T18:59:44+00:00 by Colegiu.info