根据电气设计规程的有关规定、对于一类负荷的供电、应由至少（）电源供电。
A.三个
B.两个
C.一个
D.一个加备用
参考答案：B
正常开车建立大循环系统冷运时，应注意（）等冷换设备的充分排气。
A、吸收水冷却器
B、贫/富水换热器
C、溶剂水冷却器
D、回收塔顶冷凝器
--- Did you dare to go out at night when you were a child?
--- No, I didn't. I don't have the _______ to go out at night even now.
A．power
B．ability
C．courage
D．chance
