The Grammaring Guide to English Grammar with Exercises

Types of modals

Modals include modal verbs, semi-modal verbs (also called marginal modals) and other modal expressions. They combine with main verbs and modify their meanings. A modal may have several different meanings, while similar meanings may be expressed by using different modals:

He

can't

be at home; I've just met him.

(deduction)

Unless you finish your homework, you

can't

go to the cinema.

(prohibition)

Can

I help you?

(offer)

May

I help you?

(offer)

Modal verbs

The modal verbs (or modal auxiliary verbs) are: can, could, may, might, will, shall, would, should and must.

Modal verbs always come first in a verb phrase and are followed by a bare infinitive. When used with a perfect infinitive, modal verbs usually refer to past time: I could hear the dog barking outside. (modal + simple bare infinitive)

You must be joking. (modal + continuous bare infinitive)

He may have caught the train. (modal + perfect bare infinitive)

You must have been waiting for hours. (modal + perfect continuous bare infinitive)

Contracted forms of will and would are often used in spoken and in informal written language ('ll and 'd):I'd tell you if I knew.

They'll be here soon.

Modal verbs take no -s in the third person singular: He might be at the office.

Modal verbs form their negative and interrogative like other auxiliaries and not with do: I can't swim.

Can you swim?

The following contracted negative forms are often used in spoken and in informal written language:cannot » can't

could not » couldn't

might not » mightn't

will not » won't

shall not » shan't

would not » wouldn't

should not » shouldn't

must not » mustn't

Modal verbs have no proper past tense; however, could, would, might and should may be used to refer to past time: I could swim when I was five.

Modal verbs have no infinitive, -ing or past participle forms and cannot be followed by other modal verbs. When necessary, modal idioms or other expressions are used instead of them: *If you want to be a sailor, you must can swim.

If you want to be a sailor, you must be able to swim. *I have canned swim since the age of five.

I have been able to swim since the age of five.

Semi-modal verbs

The semi-modal verbs (or marginal modals) are: dare, need, used to and ought to. They behave similarly to modal verbs but also share some characteristics with main verbs:

How

dare

she

criticise

us?

(as a modal verb, the interrogative formed without

do

)

He

didn't dare to look

back.

(as a main verb, followed by a

to

-infinitive and the negative formed with

do

)

Need

you

make

so much noise?

(as a modal verb, the interrogative formed without

do

)

You

needn't have been

so rude.

(as a modal verb, the perfect infinitive used to refer to past time)

Do

you

need to use

the hairdryer?

(as a main verb, followed by a

to

-infinitive and the interrogative formed with

do

)

They

used to live

by the sea.

(unlike a modal verb, followed by a

to

-infinitive)

You

ought to know

that by now.

(unlike a modal verb, followed by a

to

-infinitive)

Other modal expressions

Besides modal verbs and semi-modal verbs, there are other expressions which can express modal meanings. Some of these are formed with be:

be able to

be allowed to

be about to

be bound to

be going to

be likely to

be obliged to

be supposed to

etc.

Other expressions that carry modal meanings are: be to, had better, have (got) to, would rather.

Modal verbs, semi-modal verbs and other modal expressions are discussed in detail on the following pages.

Related topics:

The forms of the infinitive

The infinitive after modals

Form: future simple

Form: future continuous

Form: future perfect

Form: future perfect continuous

Subject-auxiliary inversion in questions