下列可用于等离子焊接冷却系统中冷却剂是（）。
A、盐水
B、电解质溶液
C、去离子水
参考答案：C
---It cost me 30 yuan to get here.
---Well, it was crazy of you to take a taxi you would come by bus as well.
A．unless
B．when
C．if
D．because
试述径向钻孔泵的构造及优点？
