单项选择题
When approaching a fire from win ward, you should shield firefighters from the fire by using（）
A.low-velocity fog B.high-velocity fog C.a straight stream of water D.foam spray
单项选择题 Diesel fuel vapors （）.
单项选择题 All of the following are part of the fire triangle EXCEPT （）.
单项选择题 The vapors given off by heated fuel oil are heavier than air and are（）.
