单项选择题
How should cargo tank hatches be protected when the ullage opening is open and the tank not gas free?（）.
A.With gooseneck vents B.With warning signs C.With flame screens D.With pressure-vacuum relife valves
单项选择题 Hygroscopic cargoes should be ventilated when（）.
单项选择题 I have no choice（）to put such remarks.
单项选择题 I herely request permission to（）the ship hull for routine maintenance.
