Unit 27: MODAL VERBS
Modal verbs are auxiliaries (Unit 3). They never change form. They show what we think or feel
about the lexical verb (Unit 3) in the sentence. The important modals are:
can, could, may, might, will, would, shall, should and must.
With verb formation
Put the modal verb before any other verbs. The next verb is always base form (Unit 14).
BEFORE ONE-WORD VERB FORMATIONS
[M]:MODAL [B]:BASE FORM
He [M] can [B] sell shoes very well.
The sale [M] might [B] be difficult.
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
BEFORE CONTINUOUS FORMATIONS (Unit 17)
[M]:MODAL [B]:be -ing FORM
I [M] will [B] be working tomorrow.
She [M] must [B] be buying those pants.
NOTICE: Always use be after a modal NOT am, is, are, was or were.
BEFORE PERFECT SIMPLE FORMATIONS (Unit 24)
[M]:MODAL [B]:have PAST PARTICIPLE
He [M] may [B] have worked too many hours this week.
They [M] should [B] have received their drink order by now.
BEFORE PERFECT CONTINUOUS FORMATIONS (Unit 24)
[M]:MODAL [B]:have been -ing FORM
She [M] could [B] have been taking inventory.
She [M] might [B] have been returning merchandise.
NOTICE: Always use have after a modal NOT has or had, after a modal.
As auxiliary verbs
Modals are the same as other auxiliaries for making:
QUESTIONS (Unit 9) - the modal goes before the subject:
[M] Can you help me please?
How many days [M] will you be staying?
NEGATIVE SENTENCES (Unit 5) - the modal goes before not:
He [M] couldn't return his broken cell phone.
We [M] might not hire another sales assistant.
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)
SHORT ANSWERS (Unit 11) - use the modal:
EXAMPLE: [M] Should we hire another sales assistant? Yes, we [M] should.
TAG QUESTIONS (Unit 12) - use only the modal in the tag:
EXAMPLE: We [M] wouldn't have to work so often then, [M] would we?
The important meanings of each modal verb are in the next units (28-33). Generally, modals say something about:
HOW TRUE (OR NOT TRUE) SOMETHING IS:
After that work, you [M] must be tired. = I am sure you are tired.
He [M] may have bought a sweater. = Perhaps he has bought a sweater.
HOW GOOD (OR BAD) SOMETHING IS:
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 units (28-33) will tell you the exact meanings for each verb.