问题
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In an alternating current electrical system, a low system power factor is a direct sign of _____.
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Lightning is a ________ of electrical current from
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The current death rate is reduced _______ 10% compared with that of the year of 1980.A
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The type of extinguisher which should be used for an electric fire is ______.A.carbon diox
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The amount of heat produced by this electrical apparatus is______at will by turning a smal
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The starting current of an a.cmotor is _____ the rated current.A.the same asB.much larger