OBLIGATION & ADVICE

Some Modals Verbs

HAVE TO + INFINITIVE MUST + INFINITIVE

Rules and Obligations

MUST AND HAVE TO

There’s a small difference between these two verbs:

HAVE TO is used for a general and external obligations

I have to wear a shirt and tie at work

MUST is used when the rule is imposed by the speaker

I must buy a new shirt – this one is too old now

MUST AND HAVE TO

They are also used for strong recommendations:

HAVE TOYou have to go to that restaurant – the food is

delicious

MUSTYou must go to that restaurant – the food is

delicious

LACK OF OBLIGATION OR NECESSITY

DON’T HAVE TO + INFINITIVE

PROHIBITION

MUSTN’T + INFINITIVECAN’T + INFINITIVENOT ALLOWED TO + INFINITIVE

SHOULD + INFINITIVE OUGHT TO + INFINITIVE

ADVICE

What should I do?

I can’t find my wallet.

I was sacked from my job.

This food I’ve just cooked tastes terrible.

I didn’t pass the exam.