对电容量较大的高压电气设备的绝缘状况，主要以（）的大小作为判断的依据。
A.绝缘电阻
B.吸收比
C.极化指数
D.局部放电
参考答案：B, C
A 16-year-old girl comes to the school nurse complaining of cramps, backache, and nausea with her periods. The nurse most likely would interpret these symptoms as which of the following
A．Pathologic.
B．Physiologic.
C．Psychogenic.
D．Psychosomatic.
接触线高度的安全值允许误差为（）。
A、±50mm
B、±100mm
C、±150mm
D、±200mm
