单项选择题
A cabinet or space containing the controls or valves for the fixed firefighting system must be（）.
A.posted with instruction on the operation of the systm B.ventilated and equipped with explosion-proof switches C.painted with red and black diagonal stripes D.equipped with a battery powered source of emergency lighting
单项选择题 A carbon dioxide fire extinguisher should be recharged（）.
单项选择题 A certificated lifeboatman assigned to command the lifeboat must（）.
单项选择题 A chain stripper is used to（）.
