9.Which type of gas is used to extinguish fires by reducing the oxygen concentration of the air
surrounding the fire?
(A)Hydrogen
(B)Helium
(C)Carbon-dioxide
(D)Carbon fuel
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統計: A(66), B(30), C(246), D(33), E(0) #601680
統計: A(66), B(30), C(246), D(33), E(0) #601680