Download PDF

What are Modal Auxiliary Verbs?

1. Auxiliaries verbs

The auxiliary verbs are: be, have and do they can also be main verbs. They have grammatical functions and are used for forming tenses, questions, the passive, etc. You can find out more here

2. Modal Auxiliaries

Modal auxiliary verbs are used before the infinitive of verbs to add meaning to the sentence. There are many types of meaning they can add but: possibility, permission, ability are some examples.

The Modal Auxiliary verbs are: can, could, may, might, must, ought to, shall, should, will, would and need (need can also be a main verb).


  • We can watch television.
  • We could watch television.
  • We may watch television.
  • We might watch television.
  • We must watch television.
  • We mustn’t watch television.
  • We needn’t watch television.
  • We ought to watch television.
  • We shall watch television.
  • We should watch television.
  • We will watch television.
  • We would watch television.

2. What to bear in mind when using modals

Explanation Sample sentences
Do not use modals for things which happen definitely. Water boils at 100 degrees celsius. – A modal can’t be used in this sentence.
They have no -s in the 3rd person singular. He can watch television.
Questions are formed without do/does/did. Can he speak English?
It follows a main verb in its infinitive. They can go swimming.
There are no past forms (except could and would). He was allowed to watch television.
When you use the past participle you talk about things which did not happen in the past. I could have died.

3. Long and contracted forms of modals

Affirmative Negative
Long forms Contracted forms Long forms Contracted forms
can cannot can’t
could could not couldn’t
may may not
might might not
must must not mustn’t
need need not needn’t
ought to ought not to oughtn’t to
shall ‘ll shall not shan’t
should ‘d should not shouldn’t
will ‘ll will not won’t
would ‘d would not wouldn’t