单项选择题
Current measuring instruments must always be connected in （）
A.series with a circuit B.parallel with a circuit C.series-parallel with a circuit D.delta with the shunt
单项选择题 The primary function of an electric motor is to （）
单项选择题 The power factor at which a paralleled AC generator operates is usually adjusted by the （）.
单项选择题 If the resistance of a circuit is cut in half and the applied voltage is kept constant, the current flow will be （）.
