Modals: must, should

Reference

Common mistakes

1. You mustn't wear a uniform. (meaning: it's not required) → You don't have to wear a uniform.
   mustn't = forbidden · don't have to = not required
2. You should to see a doctor. → You should see a doctor.
   Modals never take "to"
3. She musts go now. → She must go now.
   Modals never take -s
4. You don't must smoke here. → You mustn't smoke here.
   negative of must = mustn't (never don't must)

Modals: must, should — Exercises

Choose must or should

1. You _____ stop at the red light. (rule) (must / should / might)
2. You _____ drink more water. (advice) (should / must / could)
3. _____ I call her now? (asking advice) (Should / Must / Might)
4. You _____ smoke here — it's forbidden! (mustn't / shouldn't / can't)
5. We _____ leave early to avoid traffic. (should / must / could)
6. You _____ go to the doctor — you look very ill. (should / might / could)
7. After must/should, use _____. (base verb / to + verb / ing form)
8. He _____ try harder — he keeps losing every match. (should / must / might)

Complete with must/should/mustn't/shouldn't

1. You   wear a helmet — it's the law.
2. You   eat junk food — it's bad for your health.
3. You   park here — it's forbidden!
4.   I tell her the truth?

Modals: must, should — Answer Key

Choose must or should

1. must — A rule of the road → must.
2. should — Advice → should.
3. Should — Asking for advice → Should I…?
4. mustn't — It is forbidden → mustn't.
5. should — A good idea, not a rule → should.
6. should — Advice → should.
7. base verb — Modals take the base verb: should go, NOT should to go.
8. should — Advice → should.

Complete with must/should/mustn't/shouldn't

1. must
2. shouldn't
3. mustn't
4. Should