Three grammar exercises focusing on modal verbs and verb usage in English.

Here’s the complete solution with explanations for all three exercises.

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## ✔ Exercise 1: Complete using *must* or *have to*

> Key difference:
> - Must = personal obligation, strong necessity (often internal or moral)
> - Have to = external obligation (rules, laws, circumstances)

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a) Rosy left the party early. She had to get home in time to receive her guests.
→ External obligation (guests are coming — she must be there).
✔ *Had to* (past form of *have to*)

b) Students in private schools have to wear uniform.
→ Rule imposed by school → external obligation.
✔ *Have to*

c) You really must work harder to pass the exam.
→ Strong advice/urgency from speaker — personal insistence.
✔ *Must*

d) When you go to Pokhara, you must visit my relative.
→ Speaker is strongly recommending it — personal obligation/expectation.
✔ *Must*

e) I don’t like my job, sometimes I have to work at weekend.
→ External requirement (job demands it).
✔ *Have to*

f) Jenny might have to go for a check-up. She falls ill frequently.
→ Medical necessity due to health — external circumstance.
✔ *Have to*

g) He couldn’t repair his computer, so he had to call in a professional.
→ Past situation — external necessity because he lacked skill.
✔ *Had to*

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## ✔ Exercise 2: Complete using *don’t/doesn’t/didn’t have to* + verb

> Meaning: No obligation — you were free not to do it.

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a) It’s a holiday tomorrow, so we don’t have to get up early.
→ No need to wake up early on holiday.
✔ *don’t have to get up*

b) Entrance fee to the concert is free. You don’t have to pay for it.
→ Free entry → no payment required.
✔ *don’t have to pay*

c) She has got plenty of time. She doesn’t have to go yet.
→ Present simple, 3rd person singular → *doesn’t*.
✔ *doesn’t have to go*

d) David looks unique with the beard. He doesn’t have to shave it.
→ No need to remove beard — it suits him.
✔ *doesn’t have to shave*

e) My friend does everything. I don’t have to do anything unless he is ill.
→ He does it all → I’m exempt.
✔ *don’t have to do*

f) His sister got minor injury in the accident, so she didn’t have to go to hospital.
→ Past tense — minor injury → no hospital needed.
✔ *didn’t have to go*

g) Jivan is from a well-to-do family. He doesn’t have to work.
→ Wealthy → no financial pressure to work.
✔ *doesn’t have to work*

h) I might come late, so you don’t have to wait for me at table.
→ Don’t wait — I may be late.
✔ *don’t have to wait*

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## ✔ Exercise 3: Use *mustn’t* or *don’t/doesn’t have to*

> Mustn’t = prohibition (you are NOT allowed to do it)
> Don’t/doesn’t have to = no obligation (you can choose not to do it)

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a) I can stay in bed until breakfast tomorrow as I don’t have to go to work.
→ No obligation to work → can sleep in.
✔ *don’t have to*

b) Ken mustn’t worry as his parents fulfill all his desires.
→ Prohibition: “You shouldn’t worry” — reassurance.
✔ *mustn’t*

c) They mustn’t know about our plan. It should be kept a secret.
→ Prohibition: they are NOT allowed to find out.
✔ *mustn’t*

d) The lift has been repaired, so one doesn’t have to climb the stairs.
→ No need anymore — option available.
✔ *doesn’t have to*

e) One mustn’t be good to enjoy a game of Ludo.
→ Prohibition? Actually, this is odd — logically, it should be “doesn’t have to”. But grammatically, if we interpret as “you’re not required to be good”, then:
✔ *doesn’t have to* ← Correct interpretation
*(Note: “mustn’t be good” sounds like you’re forbidden from being good — illogical. So “doesn’t have to” fits better.)*

f) Whatever you do, you mustn’t neglect your studies.
→ Prohibition: don’t ever ignore studies.
✔ *mustn’t*

g) We mustn’t make so much noise. The baby might wake up.
→ Prohibition: avoid noise for baby’s sake.
✔ *mustn’t*

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## 📌 Final Answer Summary:

Exercise 1

a) had to
b) have to
c) must
d) must
e) have to
f) have to
g) had to

Exercise 2

a) don’t have to get up
b) don’t have to pay
c) doesn’t have to go
d) doesn’t have to shave
e) don’t have to do
f) didn’t have to go
g) doesn’t have to work
h) don’t have to wait

Exercise 3

a) don’t have to
b) mustn’t
c) mustn’t
d) doesn’t have to
e) doesn’t have to *(most logical)*
f) mustn’t
g) mustn’t

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✔ All answers are now complete and explained! Let me know if you’d like a printable version or further clarification.