单项选择题
A.keeps sparks from falling into an open tank B.secures covers on ullage openings C.prevents sparks from getting out of an engine's exhaust system D.grounds static electricity
A relief valve for a cargo pump is generally installed（...
单项选择题A relief valve for a cargo pump is generally installed（）.
A.after the discharge valve B.between the pump and discharge valve C.after the suction valve D.between the pump and suction valve
A gas-free certificate would usually be issued by a(n)（...
单项选择题A gas-free certificate would usually be issued by a(n)（）.
A.CCS marine surveyor B.certified marine chemist C.port engineer D.MSA marine inspector
A fire of escaping liquefied flammable gas is best exti...
单项选择题A fire of escaping liquefied flammable gas is best extinguished by（）.
A.cooling the gas below the ignition point B.cutting off the supply of oxygen C.stopping the flow of gas D.interrupting the chain reaction
