Change the sentences using should/ought to, shouldn't/oughtn't to, have to, don't have to, has to, doesn't have to
It's a good idea to brush your teeth after meals.
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It is necessary to switch off your mobile phone during exams.
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It isn't necessary for us to get up early at the weekends.
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Doctors are obliged to wear a uniform at work.
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It's not a good idea to eat in class.
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It is a teacher's duty to check students' homework.
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It's not necessary for Tom to go to football practice on Sundays.
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It's not a good idea for students to be late for the exam.
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It's not necessary for Jane to take the bus to school.
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It's a good idea to exercise to keep fit.
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It's Ruth's duty to answer phone calls and make appointments.
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It isn't necessary for students to wear a uniform at school.
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