系统有接地故障时，禁止进行什么测量？（ ）
A．用钳形电流表测量电流
B．测量接地网接地电阻
C．测量设备绝缘电阻
参考答案：B
22. The girl often helps her best friend, ______ is not good at English. To their delight, his English is improving day by day.
A．which
B．who
C．what
D．where
患者女，50岁，因“突发左小腿疼痛、无力2h”来诊。
应该考虑到的疾病有（）.
A.急性动脉栓塞
B.急性深静脉血栓
C.下肢静脉曲张
D.急性蜂窝织炎
E.急性淋巴管炎
F.动脉硬化闭塞症
