变更密级或解密,应由()。
A.密件使用单位决定
B.原定密机关、单位决定,也可以由其上级机关决定
C.国 * * 密行政管理部门指定的单位决定
参考答案:B
100与80的和,除以它们的差,商是多少?列式为100+80÷100-80.______.(判断对错)
If you do not know how to say something in English, you say: _____. [ ]
A. I don't know.
B. Excuse me. How do you say that in English?
C. I will start now.
D. I'm sorry. I don't know.