单项选择题
Besides heat, fuel, and oxygen, which of the following is necessary for a fire to exist?（）
A.Chain reaction B.Thermal action C.Chemical occlusion D.Pyrotechnical reaction
单项选择题 A fire and boat drill on a tank vessel shall, by regulation, include （）.
单项选择题 A fire in an electrical generator is considered to be （）.
单项选择题 A fire may be spread by which of the following means?（）
