Grammar Notes: Modals
Read how each group of modals works, then try the activities.
1. Obligation (necessity)
Use must, have to, have got to, or need to before the main verb when something is required or very important.
Example: Guests have to sign in at reception. You must wear a helmet on site.
2. No obligation (choice)
Don’t have to and don’t need to mean the action is not necessary—you can choose.
Example: You don’t have to print the ticket; a phone copy is fine.
3. Prohibition
Mustn’t says something is not allowed (a rule or a serious warning).
Example: You mustn’t smoke in the hospital.
4. Advice (fairly sure)
Should and ought to give advice or recommendations the speaker feels reasonably confident about.
Example: You should save your work every few minutes.
5. Advice or possibility (softer)
Might and could can suggest a gentle idea or something that is only one possible option.
Example: You could take the earlier train if you want a quieter carriage. It might rain later, so take an umbrella.