Modal verbs are auxiliaries (Lesson 3). They never change form. They show what we think or feel
about the lexical verb (Lesson 3) in the sentence. The important modals are:
can, could, may, might, will, would, shall, should and must.
Put the modal verb before any other verbs. The next verb is always base form (Lesson 14).
[M]:MODAL [B]:BASE FORM
He [M] can [B] play the piano very well.
The journey [M] might [B] be uncomfortable.
NOTICE: Modals do not have an -s form and we never use an -s form for the next verb. We say: He might come. NOT mights come or might comes
[M]:MODAL [B]:be -ing FORM
I [M] will [B] be arriving tomorrow.
She [M] must [B] be learning Arabic.
NOTICE: Always use be after a modal NOT am, is, are, was or were.
[M]:MODAL [B]:have PAST PARTICIPLE
He [M] may [B] have got lost.
They [M] should [B] have arrived by now.
[M]:MODAL [B]:have been -ing FORM
She [M] could [B] have been watching.
She [M] might [B] have been playing.
NOTICE: Always use have after a modal NOT has or had, after a modal.
Modals are the same as other auxiliaries for making:
[M] Can you help me please?
How many days [M] will you be staying?
He [M] couldn't fight his way out of a paper bag.
You [M] might not have succeeded without his help.
NOTICE: We write negative can as one word: cannot (we usually say can't)
NOTICE: In speaking, won't (= will not); shan't (= shall not)
EXAMPLE: [M] Should we tell her about it? Yes, we [M] should.
EXAMPLE: We [M] wouldn't have got there on time, [M] would we?
The important meanings of each modal verb are in the next lessons (28-33). Generally, modals say something about:
After that work, you [M] must be tired. = I am sure you are tired.
He [M] may have got lost. = Perhaps he has got lost.
You [M] must work harder. I think it is good to work hard.
They [M] should not do that. I think it is bad to do that.
The meaning of a modal verb in an affirmative sentence is not always the same as its meaning in a question or a negative sentence. The next lessons (28-33) will tell you the exact meanings for each verb.