1. You__________use your mobile phone in the exam. A. oughtn't to B. mustn't C. don't have to D. shouldn't 2. My grandparents live in the suburb. Therefore, whenever we visit them, we__________a bus. A. must take B. should take C. have to be taken D. have to take 3. We__________smoke on the bus. A. mustn't B. can't C. needn't D. mightn't 4. There are a lot of tickets left, so you__________pay for the tickets in advance. A. mustn't B. won't C. should D. don't have to 5. You__________eat plenty of fruit or vegetables every day because they are good for your health. A. oughtn't to B. mustn't C. don't have to D. should 6. You__________wash the car. I had it done yesterday. A. mustn't B. needn't C. must D. may not 7. She is a good teacher; thus, I think you__________to ask her for some advice. A. oughtn't B. must C. have D. ought 8. It's a secret. You__________let anyone know about it. A. mustn't B. needn't C. mightn't D. may not 9. Vietnamese school students nowadays__________ wear uniform. A. have to B. need to C. should D. could 10. We__________open the lion's cage. It is contrary to zoo regulations. A. must B. mustn't C. needn't D. should 11. When swimming in the pool, children__________ be accompanied by their parents. A. should B. must C. don't have to D. have to 12. If you want to maintain a good relationship, you__________behave impolitely like that. A. ought to not B. ought not to C. mustn't D. don't have 13. This drink isn't beneficial for health. You__________drink it too much A. should B. ought to not C. ought not to D. mustn't 14. This warning sign says that you__________step on the grass. A. shouldn't B. mustn't C. don't have to D. ought not to 15. I think you__________do exercise regularly in order to keep in shape. A. must B. should C. ought to D. Both B and C are correct 16. My motorbike broke down yesterday, so I__________catch a taxi to school. A. should B. ought C. must D. has better 17. You look exhausted. You__________take a rest instead of working overtime. A. should B. ought C. must D. has better 18. Those audiences__________show their tickets before entering the concert hall. A. have to B. must C. ought to D. don't have to 19. The children__________spend too much time watching TV. A. mustn't B. ought to not C. shouldn't D. Both B and c are correct 20. If you have a bad headache, you__________see the doctor. A. had better B. must C. ought D. have better