English Basic: Modal Verbs

are a part of the larger category called auxiliary verbs which are verbs that cannot be used on their own. They need to be accompanied by another (main) verb. Sometimes modal verbs are called modal auxiliaries.

The following words are modal verbs: Can, Could, May, Might, Must, Shall, Should, Will, Would.

They are modal auxiliary verbs that provide additional information about the verb that follows it.

Modal verbs are used to express ability, obligation, permission, assumptions, probability and possibility, requests and offers, and advice. Each modal verb can have more than meaning which depends on the context of that sentence (or question).

You can go now. (= permission)
I can play the guitar. (= ability)

Structure with Modal Verbs

A Modal verb is followed by another verb in the base form (the infinitive without the 'To') and they are not conjugated (we don't add an 'S' in third person). See the following structure:

Subject + Modal Verb + Verb (base form of the infinitive)

I can speak English (NOT: I can to speak English)
He can speak Spanish (NOT: He can speaks Spanish)
She can speak Spanish (NOT: She cans speak Spanish)

Modal Verbs in Negative Sentences

Subject + Modal Verb + not + Verb (base form of the infinitive)

You must not walk on the grass. (= You mustn't walk on the grass.)
He cannot speak Arabic. (= He can't speak Arabic.)
We should not be late. (= We shouldn't be late.)

As you can see in the examples above, contractions of the Modal verb + not are normally possible.

The negative of can is cannot ('not' is joined to 'can') and the contraction is can't

Modal Verbs in Questions

Modal Verb + Subject + Verb (base form of the infinitive)

May I help you?
Can I have another piece of cake please?
Would you like to come with us?

Modal	Example	Function
May	May I go to the conference?	Asking for permission.
	I may be able to help you with your project tomorrow.	Future possibility.
Might	We might be interrupting their lunch.	Present possibility.
	They might make us an offer.	Future possibility.
Can	They can fix the problem.	Ability.
	They can’t fix the problem.	Inability.
	Can I have a cup of coffee?	Request
	Can I smoke in here?	Asking for permission.
Could	Could you help me?	Request.
	Could I take tomorrow off?	Asking for permission.
	We could try unplugging it?	Suggestion.
	I could come to LA next month.	Future possibility.
	I left London, so I could get a job here.	Ability in the past.
Will	I’ll give you a call on Monday.	Promise.
	I’ll take these figures with me.	Instant decision.
	We’ll book your tickets if you like.	Offer.
	We will see an increase in salaries next year.	Certain prediction.
Would	Would you mind if I opened a window?	Asking for permission.
	Would you make me a coffee?	Request.
	Would you be available at 6pm tonight?	Making arrangements.
	Would you like to go out some time?	Invitation.
	Would you prefer the window seat or the aisle?	Preferences.
Shall	Shall I get the phone? Or will you?	Asking what to do.
	Shall I call a cab?	Offer.
	Shall we say 10pm at Roxy’s then?	Suggestion.
Should	You should see a doctor, you don’t look well.	Advice.
	We should get a specialist.	Recommending action.
	Salaries should go up next year.	Uncertain prediction.
Ought to	You ought to go to the dentist before you leave.	Advice.
Must	I must leave now to catch my train.	Obligation/ Necessity
	You mustn’t ask too many questions.	Prohibition.