单项选择题
Which is the proper method of determining whether a portable CO2 fire extinguisher needs recharging?（）
A.Check the tag to see when the extinguisher was last charged
B.Release a small amount of CO2; if the CO2 discharges，the extinguisher is acceptable
C.Weigh the extinguisher and compare the weight against that stamped on the valve
D.Recharge the extinguisher at least once each year
相关考题
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单项选择题
Which condition is necessary for a substance to burn?（）
A.The temperature of the substance must be equal to or above its fire point
B.The air must contain oxygen in sufficient quantity
C.The mixture of vapors with air must be within the explosive range
D.All of the above -
单项选择题
When retrieving the survival craft，the winch operator should stop the winch and check（）.
A.that all personnel are seated in the craft
B.that the cable has not jumped any grooves on the drum
C.which way the wind is blowing
D.the hydraulic fluid level before lifting -
单项选择题
When jumping into water upon which there is an oil-fire，you should（）.
A.break the water surface with your hands when diving head-first
B.use your hands to hold your knees to your chest
C.cover your eyes with one hand while pinching your nose shut and covering your mouth with the other
D.enter the water at the bow or stern on the windward side of the vessel
