Explanation

Modal verbs like must and should help us show obligation, advice, or probability.

1. Must

• Obligation / necessity → Something is required.

  • You must wear a seatbelt. (= It is required by law.)

• Strong probability → Something is very likely true.

  • She must be at work; her car is outside.

👉 Negative form: must not (prohibition or negative probability).

• You must not touch the wires! (= prohibition)

• He must not be hungry; he just ate. (= probably not)

2. Should

• Advice / suggestion → What is best to do.

  • You should eat more vegetables.

• Expectation / probability → Something will probably happen.

  • The train should arrive soon.

👉 Negative form: should not (shouldn’t).

• You should not lie to your parents.

Exercise 1 – Sentence Practice

1. You must answer all the questions.

2. We must obey the law.

3. You worked so hard all day. You must be tired.

4. We should not waste time.

5. You should be polite to your teacher.

6. According to the news, it should rain tomorrow.

Exercise 2 – Dialogue Practice

A: You look very pale.
B: I must be sick.
A: You should see a doctor.

A: What should I bring to the meeting?
B: You must bring your report. You should also bring a pen.

A: My son doesn’t want to go to school.
B: He must go to school! But maybe you should talk to him gently.

Exercise 3 – Rephrasing Sentences

Rewrite the sentences with must or should.

1. Don’t play with fire!

2. I suggest going to bed earlier.

3. She is probably tired.

4. It will probably be sunny tomorrow.

5. Don’t go to the party.

6. I suggest not going to the party.

Exercise 4 – Sentence Building

Tell a child the things they must / should or must not / should not do.

Word Bank: tidy up your toys, clean your room, brush your teeth, get up now, make your bed, be late, wear a coat, eat your breakfast, be polite, share your things, eat with your mouth open

Example: tell the truth → You should tell the truth!

Exercise 5 – Error Correction

Correct the mistakes in these sentences.

1. He musts go to the doctor.

2. You should not to be rude.

3. They must not late for class.

4. It should rains tomorrow.

5. We mustn’t to forget our homework.

Answer Key

Exercise 3

1. You must not play with fire!

2. You should go to bed earlier.

3. She must be tired.

4. It should be sunny tomorrow.

5. You must not go to the party.

6. You should not go to the party.

Exercise 4 (sample answers)

• You must tidy up your toys.

• You should clean your room.

• You must brush your teeth.

• You must get up now.

• You should make your bed.

• You must not be late.

• You should wear a coat.

• You must eat your breakfast.

• You should be polite.

• You must share your things.

• You must not eat with your mouth open.

Exercise 5

1. He must go to the doctor.

2. You should not be rude.

3. They must not be late for class.

4. It should rain tomorrow.

5. We mustn’t forget our homework.