8. Before taking a plane at the airport, all passengers ________ go through safety check.

　　A) can    B) must    C) may    D) ought to

　　9. — Must I put on my coat, Mum?

　　— Yes, you _______. It’s freezing outside.

　　A) may    B) can    C) must    D) need

　　10.    Some people ________ feel sick when they read a book in a car or on a boat.

　　A) can    B) may    C) must    D) ought

　　11. Students ________ be careful when they do chemical experiments in the lab.

　　A) can            B) must                C) need                D) may

　　12. It’s proved that we ________ improve our memory by using various memorizing methods.

　　A) can                 B) must                C) should            D) need

　　13. Even a small portable computer ______ store huge amounts of information.

　　A) can    B) may    C) must    D) should

　　14.        – Must I finish the task in a week?

　　– No, you ______. If you have any problem, please tell me.

　　A) can’t    B) mustn’t    C) may not    D) needn’t

　　15.    In order to keep safe, we ________ keep away from crowded places.

　　A) may    B) can     C) need     D) should