单项选择题
A.if there is sufficient oxygen to support life
B.the toxicity of flammable gases or vapors
C.the amount of CO2 present in flue gas
D.the presence of flammable gases or vapors in the air
单项选择题 A fire in a pile of linen is considered to be a class （）.
单项选择题 Your vessel is taking on bunkers from a shore side facility, if oil begins flowing from one tank vent, which of the following actions should be taken FIRST?（）
单项选择题 For which of the listed classes of fire combinations would carbon dioxide be most suitable as the extinguishing agent （）.