Modal verbs are used to express ideas such as possibility, intention, obligation and necessity.
There are not many modal verbs: can, could, dare*, need*, may, might, must, shall, should, will, would. There are also modal constructions: be able to, ought to, be allowed to.
They always come first in a verb formation, before other auxiliaries and the main verb:
{modal} + [auxiliary] + {main verb}
N.B. Modal verbs do not take a final -s for the third person singular. The verb which follows is always in the infinitive form:
He might be...
They should stay...
She could have...
We can use them with the -ing form to show continuous modality:
{modal} + {be} + {-ing}
He might be working late.
They should be coming soon.
He must be having a party.
We can use them with the past participle to show past modality:
{modal} + {have} + {past participle}
He might have been working late.
They should have seen him.
He must have gone away.
We can use be able to, be allowed to and have [got] to after modals:
{modal} + {phrase}
I will be able to...
She might not be allowed to...
They should have to...
Note that we do not use these in continuous forms.
We use modal verbs to show...
what we think or feel about a situation:
They should not have gone.
They might have been working hard.
ability to do something:
They can't speak fluently.
He could beat the record easily.
necessity:
He must stop.
They should stop.
possibility:
He could be there.
They might not win.
*DARE is regarded as a marginal modal verb because of its restricted usage - either in negative polarity or in the idiomatic "I dare say..." form. However, both structurally and semantically it does function within the system of modality, although in a limited way.
NEED can be used as an ordinary verb, meaning "must have" e.g.
I need a new coat. But in
British English, NEED can also be used as a modal verb, e.g.
You needn't pay for my dinner. In this case, there is no "s" with the 3rd person singular, and
questions and
negatives are made without "do" e.g.
Need we re ally go now?
See Also
Modals - Ability
Modals - Necessity
Modals - Offers
Modals - Permission
Modals - Possibility
Modals - Requests
Can you do my Job? - Business English activity with modal practice
