单项选择题 电容器用熔断器保护时，单台电容器可按电容器额定电流的（）倍选用熔体的额定电流。

单项选择题 （）是真空断路器的绝缘和灭弧元件。

单项选择题 Their government said that they had to use force to maintain social stability，but many people（）that it wouldn’t（）stability and harmony.