单项选择题
（），as the chemical extinguisher agent，should be used for an electric fire.
A.dry chemical or foam B.foam or soda acid C.carbon dioxide or foam D.carbon dioxide or dry chemical
单项选择题 The danger of a charged hose left unattended on deck with the nozzle open is（）.
单项选择题 No outlet on a fire hydrant may point above the horizontal in order to（）.
单项选择题 Which statement is TRUE concerning spare charges for portable fire extinguishers on unmanned tank barges?（）.
