单项选择题
An obstruction on a helodeck is any object that might present a hazard to the（）.
A.rotor blades and landing gear B.unloading of passengers C.loading of cargo D.pilot's visibility
单项选择题 An inert gas system on a tanker should be used to（）.
单项选择题 An inert gas system installed on a tanker is designed to（）.
单项选择题 All ships（）suspected infectious disease on board should radio information to Port Health Officer.
