单项选择题
A.the gasoline tank is full B.the bilges，cabins，etc. are thoroughly ventilated C.you have fresh water on board D.Each of the above is followed
Before entering a tank，always check the vapor content（）...
单项选择题Before entering a tank，always check the vapor content（）a combustible gas indicator.
A.with B.by C.of D.for
After the initial cleaning of flue gas in an inert gas ...
单项选择题After the initial cleaning of flue gas in an inert gas system the gas is passed through what device for final cleaning?（）.
A.Scrubber B.Demister C.Deck water seal D.Final filter
According to the regulations，to prevent excessive press...
单项选择题According to the regulations，to prevent excessive pressure buildup in cargo tanks containing LFG，they are fitted with（）.
A.pressure vacuum relief valves B.excess flow valves C.safety relief valves D.flame screens
