If your asphalt barge has operated more than 12 months in saltwater in the 24 month period since it was last dry-docked，when is it required to be hauled out again? （）

单项选择题If the meter needle of the oxygen indicator cannot be set to zero，what should be done? （）

A.Replace the batteries
B.Check the sampling tube for blockage
C.Adjust the final reading by the amount the needle is displaced from zero
D.Replace the platinum filament

单项选择题If dangerous goods have been thrown overboard by the Shipowner or the master，（）can be made liable for their loss.

A.either
B.the master
C.the Shipowner
D.neither

单项选择题I am（）fire and have dangerous cargo on board.

A.on
B.in
C.at
D.with

单项选择题Goods may be dangerous not merely by reason of the fact that they may endanger the safety of the vessel，but also because they are liable to cause the vessel to be（）.

A.despatched
B.detained
C.detected
D.delivered

单项选择题Dangerous goods required to be “carried on deck only” should not be carried on closed vehicle decks，but may be carried on open vehicle deck when authorized by the competent authority concerned. （）

A.under deck
B.on deck
C.ondeck only
D.under deck only