电路是为了获得（）而使用的电气元件和电气设备的总称。
A.电压
B.功率
C.电流
D.电感
参考答案：C
The majority of doctors _____ smoking is harmful to health. [ ]
a. are believed
b. had believed
c. has believed
d. believe
电压互感器高压熔断的原因主要有哪些？
