单项选择题
The frequency of an alternator is controlled from the main switchboard by adjusting the（）
A.frequency meter B.voltage regulator C.governor control D.sychroscope switch
单项选择题 The frequency of an AC generator is controlled by the （）
单项选择题 Capacitance is the property of an electric circuit opposing a change in the （）
单项选择题 Inductance is the property of an electric circuit that （）
