Modal verbs:

  • They never change their form. You can't add "s", "ed", "ing"...
  • They are always followed by an infinitive without "to" (e.i. the bare infinitive.)
  • They are used to indicate modality allow speakers to express certainty, possibility, willingness, obligation, necessity, ability



I can swim. (Ability)

Can I use your phone please? (Permission)

Can we visit Grandma at the weekend? (Suggestion)

It can get very hot in Arizona. (Possibility)

When I was younger I could run fast. (Ability in the past)

Excuse me, could I just say something? (Polite permission)

May I help you? (Polite suggestion)

You should / ought to revise your lessons. (Advice)

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