单项选择题
Is this a （）(淡水) tank?
A. bilge water B. ballast water C. fresh water D. sea water
单项选择题 That is the （）(污水井).
单项选择题 It is a （）(压载水) tank.
单项选择题 From the waterline to the ship’s（）(底部) is called draft.
