Verbs: modals of obligation


To express obligation, we can use must and have to. To express light obligation or advice, we can use should and had better.


  • You must see a doctor at once!
  • You must answer all questions.
  • I have to be at the airport by 7am.

Light obligation or advice:

  • You should stop smoking as soon as possible.
  • You had better check about the visa situation before you fly there.
Further learning
Description Author Language
Explanation of the differences between 'must' and 'have to'. Oxford English Now
The difference between 'must' and 'have to' BBC Learning
The difference between 'must not' and 'don't have to'. BBC Learning