低压防爆开关的换向开关及接触器的触头接触电阻，应不大于（）
A.300微欧
B.1000微欧
C.150微欧
D.600微欧
参考答案：A
意志行动的基础是
A．设立目标B．克服困难C．随意运动D．实施行动E．选择行动方式
We might need more food,_ how many people turn up. [ ]
A. depending on
B. going on
C. having on
D. looking on
