单项选择题
Which extinguishing agent is most effective on a mattress fire?（）
A.CO2 B.Foam C.Dry Chemical D.Water
单项选择题 Which extinguishing agent is effective in combating an isoprene fire?（）
单项选择题 Which extinguishing agent is best for use on a magnesium fire?（）
单项选择题 Which characteristic of Halon is a disadvantage when it is used as a fire extinguishing medium?（）
