Are you clear about the job of a policeman，Ben？
Yes，to keep people ________ and the society in good order．（ ）
A．busyB．safeC．luckyD．healthy
The girl in the classroom ______ be Sarah．She has gone to the library．（ ）
A．mayB．mustC．can'tD．needn't
We have worked so long．Shall we stop ______ a rest？（ ）
A．haveB．to havingC．havingD．to have
Rules are helpful to us，______ we have to follow them．（ ）
A．soB．butC．orD．because
Tim is going to give his father a surprise ______ Father's Day．（ ）
A．inB．atC．onD．by
Ladies and gentlemen，attention please!I have ______ important to tell you．（ ）
A．nothingB．somethingC．everythingD．anything