Explanation
Exercises

✅ Must vs Have to · 🚫 Mustn’t vs Don’t have to

Obligation & rules (internal vs external), prohibition vs lack of necessity, and the correct forms for negatives, questions, past and future.
must + base verb (no “to”) mustn’t = prohibition have to / don’t have to = necessity / no necessity past: had to · future: will have to questions with do/does/did for have to “Must we…?” = formal/less common have got to (BrE) / gotta (informal)
🧩Form — MUST
HOW TO SAY IT
  • must + base verb: I must practise my English every day. (not *must to practise)
  • mustn’t + base verb (negative): You mustn’t use your phone during the test.
  • Must is a modal → no -s after he/she/it: He must revise. (not *musts)
  • Questions (formal/rare): Must we finish this exercise today?
  • No past/future forms: use had to / will have to for time reference.
  • ✗ We don’t must speak now. → ✓ We mustn’t speak now.
  • ✗ Yesterday I must study late. → ✓ Yesterday I had to study late.
⚙️Form — HAVE TO
HOW TO SAY IT
  • Affirmative: I have to do my homework. / He has to do his homework.
  • Negative (no obligation): I don’t have to write a long answer.
  • Questions: Do you have to learn these words? / Did you have to take notes?
  • Past: I had to listen twice. · Future: We will have to take a test next week.
  • ✗ I ’ve to practise. → ✓ I have to practise.
BrE option
  • Have you got to do the homework today? (= Do you have to…?) · Informal: I’ve got to go! (spoken gotta)
🧠Meaning — MUST vs HAVE TO
OBLIGATION
  • must = obligation from the speaker’s viewpoint (internal / personal):
    “I must practise pronunciation.” · “You must be on time for class.”
  • have to = external rule/requirement:
    “We have to bring a notebook.” (teacher’s rule)
🚦Mustn’t vs Don’t have to
  • mustn’t = prohibition (it is necessary not to do it):
    “You mustn’t look at other students’ answers.”
  • don’t have to = no necessity (it’s optional):
    “You don’t have to finish it now; you can do it tomorrow.”
  • ✗ You mustn’t practise if you don’t want to. (means ‘it’s forbidden to practise’)
    ✓ You don’t have to practise if you don’t want to. (not necessary)
🗣️Naturalness
  • Everyday English prefers Do we have to…? over formal Must we…?
  • Use mustn’t for rules: You mustn’t talk during the listening.
  • Use don’t have to to remove obligation: We don’t have to write it in full sentences.
🧪More examples
  • I must remember to practise these new words.
  • Students have to bring their books to class. (rule)
  • She didn’t have to translate every word; the text was easy. (no need in the past)
  • You will have to do a short test next week. (future necessity)
  • You mustn’t use a dictionary during the test. (prohibition)
🚫Common mistakes
  • ✗ He musts practise. → ✓ He must practise.
  • ✗ We don’t must be quiet. → ✓ We mustn’t be noisy.
  • ✗ You will must do homework. → ✓ You will have to do homework.
  • ✗ Have you to write it? → ✓ Do you have to write it?
  • ✗ I ’ve to go. → ✓ I have to go.
✅Quick checks
  • Internal/strong personal rule? → must
  • External rule/requirement? → have to
  • Prohibited? → mustn’t
  • Optional / not necessary? → don’t have to
  • Past / future obligation? → had to / will have to
  • Questions/negatives with have to? → use do/does/did
Recap: must (speaker-imposed) vs have to (externally imposed). mustn’t = forbidden; don’t have to = not necessary. Past/future only with have to → had to / will have to. Keep forms clean: no “to” after must, no “musts”, and use do/does/did with have to. 💡
Exercises:
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Must vs Have to; Mustn’t vs Don’t have to

1
Students bring their ID cards to the exam hall.
2
You pay for the museum — it's free today.
3
Engineers wear safety goggles on site.
4
He leave early; the workshop finished at noon.
5
You park across the fire exit.
6
She wear a uniform at her school.
7
We submit the report by Friday.
8
I bring lunch today — we're eating out.
9
Visitors keep their phones on silent in the gallery.
10
They tell anyone the password.

Must vs Have to; Mustn’t vs Don’t have to

1
You ____ park here — it’s for emergency vehicles only.
A.
B.
C.
2
It’s a casual meeting; you ____ wear a suit.
A.
B.
C.
3
Do we ____ submit the form by Friday, or is Monday okay?
A.
B.
C.
4
The sign says “No phones.” You ____ use your phone in the lab.
A.
B.
C.
5
I ____ leave early today; my doctor is waiting at 5.
A.
B.
C.
6
We ____ bring snacks; the organizer will provide food.
A.
B.
C.
7
It’s your first day tomorrow — you ____ be late.
A.
B.
C.
8
You ____ read this book — I’m sure you’ll love it!
A.
B.
C.
9
In most countries you ____ have a passport to travel abroad.
A.
B.
C.
10
Cyclists ____ wear helmets by law in this city.
A.
B.
C.

Must vs Have to; Mustn’t vs Don’t have to

Form tips: Do/Does + S + have to + V? Did + S + have to + V? (past Q) S + don’t/doesn’t have to + V (no necessity) S + didn’t have to + V (past) must = strong rule; mustn’t = prohibition (≠ don’t have to)

EXAMPLE — Interviewer: What did you have to do (you/do) during your probation? — Maya: I had to prepare (prepare) reports every day.

1
INTERVIEWER: (you/work) at night?
2
MAYA: Yes, I (work) night shifts once every two weeks.
3
INTERVIEWER: (you/wear) a uniform?
4
MAYA: No, we (wear) a uniform, but we must wear our ID badges.
5
INTERVIEWER: Before you joined this company, (you/take) any certification exams?
6
MAYA: Yes, I (study) for three months and pass two tests.
7
INTERVIEWER: (your manager/sign) every travel request?
8
MAYA: Visitors (switch off) their phones near the machines.
9
MAYA: When I worked at the call center, we (work) on public holidays.
10
MAYA: Now we (stay) late unless there’s an incident.