单项选择题
Upon arrival at the discharging port, the inert gas system is（）.
A.turned on B.turning on C.turn on D.to turn on
单项选择题 Vessels are required（）Singapore Port Service when passing the points indicated.
单项选择题 Vessels are warned（）in this area.
单项选择题 Vessels carrying（）must not willfully wash decks or holds.
