警察是国家机器的重要组成部分，是阶级专政的重要工具，具有鲜明的阶级性。 ( )
参考答案：对
— I'm really confused on how to balance my interest and study.
— Well, turn to your teacher for advice, in my opinion, _____ you'll make it. [ ]
A. but
B. and
C. so
D. unless
4230（）
A．A
B．B
C．C
D．D
