单项选择题
A.current in the circuit
B.voltage in the circuit
C.inductance in the circuit
D.resistance in the circuit
单项选择题 Inductance is the property of an electric circuit that （）
单项选择题 The operator of electrical motors should keep a constant check on the loads they carry because （）
单项选择题 Which of the listed sections of an emergency switchboard is used to supply power for alarm signals under emergency conditions?（）