单项选择题
A.danger to crew and cargo
B.necessity of periodic inspection
C.possible need to jettison
D.All of the above
单项选择题 It is generally NOT allowed to clean up an oil spill by using（）.
单项选择题 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? （）