Must, Have to, Should
Modal verbs for obligation, prohibition and advice.
Obligation: must and have to
must = the speaker feels it's necessary; have to = a rule or obligation from outside.
I must call my mum tonight.personal feeling
We have to wear a uniform at work.a rule
mustn't and don't have to
Careful — the meaning is completely different! mustn't = not allowed; don't have to = not necessary.
You mustn't smoke here.it's forbidden
You don't have to come if you're busy.it's not necessary
Advice: should and ought to
should and ought to mean the same — giving advice. should is much more common.
You should see a doctor.
You ought to apologise.
You shouldn't eat so much sugar.
Tip: After must and should the verb has no to: “You must to go” ✗ → “You must go” ✓.
Sample quiz questions
- You ___ smoke in the hospital. It's forbidden.
- It's Sunday. I ___ get up early.
- You look tired. You ___ go to bed.
- The sentence “You must to wear a helmet.” is grammatically correct.
Take the interactive quiz for this lesson (6 questions)
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