单项选择题
Water is a very effective fire extinguishing agent because it（）
A.will remove all the toxic fumes from the air B.has the greatest cooling ability C.will leave no harmful residue D.completely removes combustible vapors from the air
单项选择题 A large oil fire is best extinguished with（）
单项选择题 Fires in escaping flammable gas are quickly brought under control by（）
单项选择题 If a fire occurs in the boiler room because of a leaking fuel line to a burner, you shut off the fuel using the（）
