B. GRAMMAR I. Choose the best answer 1. 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 2. She is a good teacher; thus, I think you__________ ask her for some advice. A. oughtn't B. must C. have to D. ought to 3. You __________use your mobile phone in the exam. A. oughtn't to B. mustn't C. don't have to D. shouldn'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. Peter has been working for 10 hours. He……………be very tired now. A. needn't B. must C. has to D. should 7. Vietnamese school students nowadays__________ _ wear uniform. A. have to B. need to C. should D. could 8. You look totally exhausted. You ____ take a rest instead of working overtime. A. should B. ought C. must D. has better 9. You ____ tell anyone what I've revealed to you. It's still a secret. A. mustn't B. had better not C. ought not to D. don't have to 10. We ____ go to work by car. Sky train is a wise choice during rush hour. A. ought to B. mustn't C. shouldn't D. have to II. Complete the sentences, using should(not)/ ought (not)/ must/ mustn’t/ (not) have to 1. Your grandparents live far from us, so you _________ talk to them on the phone regularly. 2. I can watch TV and play computer games on Sunday because I _________ go to school that day. 3. I _________ stay overnight at my friends’ house. My parents are very strict about this. 4. She _________stay at home to look after her children because there is no one to help her. 5. You _________ to talk to your grandparents more often so that you can understand them better.