单项选择题
What is NOT a characteristic of carbon dioxide fire-extinguishing agents?（）
A.Effective even if ventilation is not shut down B.Will not deteriorate in storage C.Non-corrosive D.Effective on electrical equipment
单项选择题 What is meant by the term overhaul in firefighting?（）
单项选择题 What is best suited for fighting a fire in a ballast control room?（）
单项选择题 What is an advantage of using foam in fire fighting?（）
