III.

1. have to

2. must

3. shouldn't 

4. don't have

5. should

6. have to

7. mustn't

8. must

9. don't have

10. should

IV.

1.a should

2.b don't have to

3.d have to

Children  must / have to  start school when they are five.

2.

In many countries, you  should / must  wear a seat belt in the car - it’s the law.

3.

  I know you like sugar but you  shouldn’t / don’t have  to eat quite so much - it’s bad for you.

4.

     I’m not working tomorrow, so I  mustn’t / don’t have  to get up early.

5.

The manager suggested that we have to / should  try to find another hotel.

6.

          Kids  should / have  to wear a life vest. That’s bur regulation.

7.

      You mustn’t / don’t have to smoke in here; smoking isn’t allowed in the airport.

8.

     You  must / should  hand in your homework on Tuesday or your mark will be zero.

9.

        You  have to / don’t have to dress up for the party. Wear whatever you feel comfortable in.

10.

      You  should / have to  ask the teacher to help you if you don’t understand the lesson.

,

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                    CHO MÌNH CÂU TRẢ LỜI HAY NHẤT NHÉ <3