A.FoamB.Solid stream water nozzleC.All-purpose nozzleD.……

单项选择题When fighting a fire with a portable dry chemical fire extinguisher，the stream should be directed（）.

A.over the top of the flames
B.off a bulkhead into the fire
C.in front of the fire
D.at the base of the fire

单项选择题When fighting a fire on a bulkhead using a portable carbon dioxide extinguisher，the stream should be directed at the（）.

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（）.

A.protect themselves from smoke
B.obtain the best available air
C.allow the heat and steam to pass overhead
D.All of the above

单项选择题When electrical equipment is involved in a fire，the stream of dry chemicals should be（）.

A.aimed at the source of the flames
B.fogged above the equipment
C.shot off a flat surface onto the flames
D.used to shield against electrical shock

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（）.

A.is not an effective agent on Class B fires
B.does little or no cooling
C.dissipates quickly
D.is rapidly absorbed by the liquid