11.You look really tired. You _________ take a few days off and have a holiday. a. should b. must c. have to d. can 12.In Vietnam, you _________ take a deep bow as you do in Japan. a. mustn’t b. don’t have to c. should d. shouldn’t 13.Sorry, but my train is at 6.00. I _________ leave now. a. shouldn’t b.ought to c.mustn’t d. have to 14.You _________ look at other students’ work. It’s against the rules. a. shouldn’t b.don’t have to c. mustn’t d. can’t 15.The airline only allows two pieces of luggage. You _________ pack too much! a. shouldn’t b. mustn’t c. don’t have to d. couldn’t 16.John can’t come because he _________ work tomorrow. a. should b.can c.must d. has to 17.I know they enjoy their work, but they ______ work at the weekends. It’s not good for them. a. shouldn’t b.don’t have to c. mustn’t d. have to 18.Elderly people _________ be treated with great respect a. shouldn’t b. should c.aren’t obliged to d. mustn’t 19.He _________ use chopsticks for spring roll. It is finger food. a. must b.has to c.doesn’t have to d. should 20. Everyone _________ wear a helmet when riding a motorbike. It’s mandatory according to traffic law. a.isn’t allowed to b. must c. can d. shouldn’t