Obligation: Must, Have To and Mustn't: A2 Exercises

Every answer with the reason behind it. Read the explanation for the ones you got right as well — that is where you find out whether you were right for the right reason.

Multiple choice questions — answers

1. You ___ wear a helmet on a building site. → must

Must is a modal and takes the base form with no to.

2. She ___ work on Saturdays in her new job. → has to

Have to is an ordinary verb, so the third person takes has.

3. You ___ smoke in here — it's forbidden. → mustn't

Mustn't expresses prohibition.

4. You ___ come if you're busy — it's optional. → don't have to

Don't have to means it is not necessary.

5. We ___ leave early yesterday because of the traffic. → had to

Must has no past form, so had to is used.

6. ___ I bring anything to the party? → Do I have to

Have to forms questions with do, unlike a modal.

7. Which sentence means it is forbidden? → You mustn't tell her.

Mustn't is the prohibition; the others all mean it is unnecessary.

8. He ___ take the medicine three times a day. → has to

The third-person singular of have to is has to.

9. Passengers ___ keep their seatbelts fastened. → must

Must expresses a strong rule, followed by the base verb.

10. I ___ get up early tomorrow — my flight is at six. → have to

An external circumstance imposes the necessity, so have to is natural.

11. You ___ pay now; you can pay when you collect it. → don't have to

The second clause shows it is optional, not forbidden.

12. We ___ be quiet in the library. → must

Must is used for a rule the speaker accepts.

13. ___ she work at weekends? → Does she have to

Have to takes does in a third-person question.

14. You ___ touch that wire — it's live. → mustn't

A danger warning takes mustn't.

15. They ___ wait two hours at the border last week. → had to

A past necessity takes had to.

16. Which sentence is correct? → He must go now.

Modals are followed directly by the base form.

17. I'll ___ ask my manager first. → have to

Must has no infinitive, so have to follows will.

18. You ___ be over eighteen to enter. → must

A rule stated impersonally often uses must.

19. We ___ book — the restaurant is never full on Tuesdays. → don't have to

Booking is unnecessary rather than forbidden.

20. Which sentence describes a rule from outside the speaker? → I have to wear a uniform at work.

The uniform rule comes from the employer, not from the speaker.

Fill-in-the-blank questions — answers

1. You ___ wear a seatbelt in the back as well. → must

Must states a strong rule, followed by the base verb.

2. She ___ to travel to Ankara twice a month. → has

The third-person singular of have to is has to.

3. You ___ use your phone during the exam. → mustn't

Mustn't expresses prohibition.

4. You ___ have to come if you'd rather stay at home. → don't

Don't have to means it is not necessary.

5. We ___ to wait an hour for a table last night. → had

A past necessity takes had to.

6. ___ I have to bring my passport? → Do

Have to forms questions with do rather than by inversion.

7. He ___ to be at the airport by six tomorrow. → has

Third person singular takes has to.

8. Visitors ___ sign in at reception. → must

A stated rule takes must with the base verb.

9. You ___ tell anybody — it's a surprise. → mustn't

A prohibition takes mustn't.

10. I'll ___ to check the timetable first. → have

Must has no infinitive, so have to follows will.

11. They didn't ___ to pay for the tickets. → have

The past negative of necessity is didn't have to.

12. ___ she have to work on public holidays? → Does

A third-person question with have to uses does.

13. You ___ walk on the grass in this park. → mustn't

A park rule forbidding something takes mustn't.

14. We ___ to leave before the interval, unfortunately. → had

Had to expresses a past obligation.

15. I ___ remember to post that letter today. → must

Must often carries the speaker's own sense of obligation.

16. You don't ___ to book in advance on weekdays. → have

Don't have to means the action is optional.

17. Everybody ___ to show identification at the gate. → has

Everybody is grammatically singular, so it takes has to.

18. We ___ be late — the ceremony starts at noon exactly. → mustn't

Mustn't forbids an outcome rather than permitting it.

19. Do you ___ to wear a uniform in that school? → have

A question about an external rule uses do plus have to.

20. She ___ to cancel her holiday because of the operation. → had

A past necessity imposed by circumstances takes had to.

Sentence structure: word ordering — answers

1. State a safety rule at work. → You must wear a helmet on site.

State a safety rule at work.

2. Describe an obligation imposed by a job. → She has to work every other Saturday.

Describe an obligation imposed by a job.

3. Forbid parking in a specific place. → You mustn't park in front of the gate.

Forbid parking in a specific place.

4. Tell somebody a reply is optional. → You don't have to answer that question.

Tell somebody a reply is optional.

5. Report a past necessity. → We had to wait two hours yesterday.

Report a past necessity.

6. Ask whether a document is required. → Do I have to bring my passport?

Ask whether a document is required.

7. Describe a doctor's instruction. → He has to take the medicine daily.

Describe a doctor's instruction.

8. State a rule on public transport. → Passengers must keep their tickets.

State a rule on public transport.

9. Forbid a careless habit. → You mustn't leave the door unlocked.

Forbid a careless habit.

10. Announce a future necessity. → I will have to ask my manager.

Announce a future necessity.

11. Report that a cost was waived. → They didn't have to pay anything.

Report that a cost was waived.

12. Ask about somebody's job requirements. → Does she have to travel for work?

Ask about somebody's job requirements.

13. State an obligation the speaker feels. → We must leave before the traffic starts.

State an obligation the speaker feels.

14. Reassure somebody that a booking is unnecessary. → You don't have to book on weekdays.

Reassure somebody that a booking is unnecessary.

15. State a rule for all visitors. → Everybody has to sign in at reception.

State a rule for all visitors.

16. Report a past obligation you could not avoid. → I had to cancel my appointment.

Report a past obligation you could not avoid.

17. Forbid phone use in a quiet room. → You mustn't use your phone in here.

Forbid phone use in a quiet room.

18. Ask about a dress code. → Do we have to wear formal clothes?

Ask about a dress code.

19. Draw a confident conclusion about somebody. → She must be very tired after that.

Draw a confident conclusion about somebody.

20. Report a necessity during a journey. → We had to change trains in Vienna.

Report a necessity during a journey.