Rewrite the sentences using should/ought to, shouldn't/oughtn't to, have to, don't have to, has to, doesn't have to.

1. You should brush your teeth after meals. 2. You have to switch off your mobile phone during exams. 3. We don't have to get up early at weekends. 4. Doctors have to wear a uniform at work. 5. You shouldn't eat in class. 6. A teacher has to check students' homework. 7. Tom doesn't have to go to football practice on Sundays. 8. Students shouldn't be late for the exam. 9. Jane doesn't have to take the bus to school. 10. You should exercise to keep fit. 11. Ruth has to answer phone calls and make appointments. 12. Students have to wear a uniform at school.