单项选择题
What is required in addition to the heat，fuel，and oxygen of the fire triangle to have a fire?（）
A.Electricity B.Chain reaction C.Pressure D.Smoke
单项选择题 What is NOT listed on the metallic name plate required to be attached to hand portable fire extinguishers?（）
单项选择题 What is NOT a characteristic of carbon dioxide fire-extinguishing agents?（）
单项选择题 What is meant by the term overhaul in firefighting?（）
