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單項(xiàng)選擇題

One disadvantage of using regular dry chemical (sodium bicarbonate) in firefighting is that().

A.it can break down under high heat and emit noxious fumes
B.it will decompose under prolonged storage and lose its effectiveness
C.fire has been known to flash back over the surface of an oil fire
D.it is ineffective in fighting fires in high-voltage electrical equipment

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