24 Can: Modals of Ability



A modal verb is a type of auxiliary (helping) verb that has no meaning on its own but it modifies the main verb, changes its meaning and gives more details about the action.

The verb can is a modal verb used to express the idea of ability or opportunity, to express the possibility or impossibility of an event or action happening and to ask for or give permission.


The modal verb can is used as an auxiliary verb and has three forms:


Its structure, in the affirmative form, is:
Subject + can + verb + …

Subject can Verb
I can work
You can work
He can work
She can work
It can work
We can work
You can work
They can work


Its structure, in the negative form, is:
Subject + cannot + verb + …

  • Short form of the negative form is can’t;
  • Can is an exception in forming the negative form and it is written together with not: cannot (can not is incorrect).
Subject cannot Verb
I cannot work
You cannot work
He cannot work
She cannot work
It cannot work
We cannot work
You cannot work
They cannot work


Its structure, in the interrogative form, is:
Can + subject + verb + …?

Modal Verb Subject Verb Question Mark
Can I work ?
Can you work ?
Can he work ?
Can she work ?
Can it work ?
Can we work ?
Can you work ?
Can they work ?


  1. Ability
    • She can play the piano.
    • She cannot play the piano.
    • Can she play the piano?
  2. Offer
    • Can we help you and your husband?
  3. Request
    • Can you open the window, please?
  4. Possibility
    • My wife can go to Milan this summer.
  5. Opportunity
    • We can stay at his place for a week!
  6. Permission
    • My children can stay at the party.
    • My children cannot stay at the party.
  7. Reproach
    • Can’t you just tell him your marital status?
  8. General truth
    • Parks can be dangerous.


We use can to express:

  1. Abilities: to be able to do something;
  2. Offers: to make offers;
  3. Requests: to demand something;
  4. Possibilities: to talk about possible situations;
  5. Opportunities: to express the chance to do something;
  6. Permission: to ask or give permission;
  7. Reproaches: to tell someone what we want them to do;
  8. General truths: to talk about things that are usually true;


The modal verb can express ability, offer, request, possibility, opportunity, permission, reproach and general truth.

The structures are:

  • Affirmative: Subject + can + verb + …
  • Negative: Subject + cannot + verb + …
  • Interrogative: Can + subject + verb + …?

For example:
— Affirmative: “She can play the piano.”
— Negative: “She can’t play the piano.”
— Interrogative: “Can she play the piano?

NOTE: The form is always the same, even for the third person singular.

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