A. Complete each sentence with the correct modal (must, mustn't, should, shouldn't).
1. I______take some exercise if I want to feel fine.
2.I______ worry about the exam if I were you. You have worked really hard.
3.You look tired. I think you______take a few days off.
4.You______swim in that river. It's full of crocodiles.
5. You______ drink so much. It's not good for your health.
6.You______brush your teeth after every meal,if possible.
7.You______touch anything electrical if you are in the bath.
8.You______focus more on your family and less on work.
9.Jenny,you______play in the street.
10.You_____come to school on time.​