English as an Additional Language: English Modals

Modal Structure

Modal Verbs

Modal verbs include can, must, may, might, will, would, should, ought to, had better. They are used with other verbs to express ability, obligation, possibility, probability, necessity, permission and so on.

Modal verbs lend different shades of meaning to the main verb to which they are attached and help to express the mood or attitude of the speaker.

Watch the video below to learn about modals and how to use them.

Modals

Read the hand out below for more information on modals.

See the table below to understand degrees of certainty and modal use.

**Degrees of Certainty**
Certain (100%)	Near Certainty (90%)	Near Impossibility	Less certain (50%)
No Modal	Must Have Have got to	Can't Couldn't	May Might Could

Final Notes

Modal verbs do not change their form (spelling), and they have no infinitive or participle (past/present). The modals must and can need substitute verbs to express obligation or ability in the different tenses. Here are some examples:

Past simple: I couldn't/wasn't able to read until I was 6 years old.
Present perfect: I haven't been able to solve this problem. Can you help?
Future: I'm not sure if I will be able to come to your party.
Infinitive: I would love to be able to play the piano.

NOTE: Modals do not need an additional auxiliary in negatives or questions.

1. Simple modals use one form for all persons (I, you, he/she, we and they). They are used in the present and future.

The form is modal + base
E.g. You must be on time. She had better leave soon.

2. Perfect modals:

They are used to show degree of necessity in the past.

The form is modal + have + past participle
E.g. You should have studied for the test last week.

Note: There are also modal-like expressions, which have the same or similar meaning of modals. E.g.: have to, have got to, be allowed to (like 'must') ought to (like 'should')