单项选择题
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
A chemical additive to LPG gives it a characteristic（）....
单项选择题A chemical additive to LPG gives it a characteristic（）.
A.odor B.color C.pressure D.density
