Must / Have To (Obligation)

Use 'must' and 'have to' to express obligation or necessity. 'Mustn't' means something is forbidden, while 'don't have to' means there is no obligation.

Post
Level B1 Modals

Summary

  1. Use 'must' and 'have to' to express obligation or necessity. 'Mustn't' means something is forbidden, while 'don't have to' means there is no obligation.
Structure
subject + must/have to + base verb

Examples

  1. You must wear a seatbelt in the car.
  2. I have to work on Saturday this week.
  3. You mustn't smoke in here.
  4. You don't have to come if you're busy.

Common mistakes

  • Don't confuse 'mustn't' and 'don't have to': 'mustn't' = forbidden, 'don't have to' = not necessary.
  • Use 'had to' for the past: NOT 'I must go yesterday' → 'I had to go yesterday.'

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