1. Here is a very short explanation: 

      ​Must

      • Use for: Strong obligation or advice (from the speaker).
      • Example: You must wear a seatbelt.

      Mustn't

      • Use for: Prohibition; something is not allowed.
      • Example: You mustn't park here.

      Have to

      • Use for: Obligation due to rules or laws.
      • Example: I have to go to work at 9.

      Don't Have to

      • Use for: No obligation; optional.
      • Example: You don't have to come if you're busy.

        ____________________________________

      • Must = strong necessity
      • Mustn't = not allowed
      • Have to = required by rules
      • Don't have to = optional
English Modal Verbs Exercise

1. You ______ finish your project by tonight.
a) Must
b) Have to

2. You ______ eat sweets because of your diet.
a) Mustn't
b) Don't have to

3. We ______ leave early to catch the first train.
a) Must
b) Have to

4. I ______ wear a uniform at work.
a) Have to
b) Must

5. You ______ help me if you don’t want to.
a) Don't have to
b) Mustn't

6. We ______ submit the report until next week.
a) Don't have to
b) Must

7. She ______ talk during the exam.
a) Mustn't
b) Have to

8. You ______ be late for your flight.
a) Must
b) Mustn't

9. They ______ stay the whole night.
a) Must
b) Don't have to

10. He ______ apologize for his mistake.
a) Must
b) Have to