单项选择题
A.stop ventilation
B.stop the vessel
C.de-energize the circuit
D.apply water to extinguish the fire
单项选择题 An extinguishing agent which effectively cools，dilutes combustible vapors，removes oxygen，and provides a heat and smoke screen is（）.
单项选择题 An engine compartment gasoline fire requires which type of extinguisher?（）.
单项选择题 An effective method for moving patients with spinal injuries onto a spine board is known as the（）.