在制（）系统和发电机（）冷却系统上取样，必须事先与有关值班人员联系，并应遵守电业安全工作规程的有关规定。
参考答案：氢；氢
The present situation is very complex,so I think it will take me some time to________its reality.[ ]
A. make up
B. figure out
C. put off
D. look through
两汉儒学独尊为什么会养成一个士大夫阶层？
