单项选择题
Halon from extinguishers used on a class B fire，should be directed（）.
A.at the top of the flames B.at the base of the fire near the edge C.in short quick bursts D.toward the upwind side of the fire
单项选择题 Halon fire extinguishers are NOT effective when used on which types of fires?（）
单项选择题 Halon extinguishes fire primarily by（）.
单项选择题 Halon extinguishes a fire by（）.
