单项选择题
A.base of the flames，moving the horn from side to side，following the flames upward as they diminish
B.top of the flaming area，moving the horn from side to side，following the flames downward as they diminish
C.center of the flaming area，moving the horn vertically from top to bottom
D.bottom of the flaming area，moving the horn vertically to the top following the flames upward as they diminish
单项选择题 When fighting a fire in an enclosed space，the hose team should crouch as low as possible to（）.
单项选择题 When electrical equipment is involved in a fire，the stream of dry chemicals should be（）.
单项选择题 When dry chemical extinguishers are used to put out class B fires，there is a danger of reflash because dry chemical（）.