When fire pumps are used for other than firefighting service，each pipe connecting the other service (except for branch lines used for deck washing) must have a（）.

单项选择题When fighting an oil or gasoline fire in the bilge，which of the following should NOT be used?（）

A.Foam
B.Solid stream water nozzle
C.All-purpose nozzle
D.Carbon dioxide

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