单项选择题
Before entering the chain locker，you should（）.
A.have someone standing by B.make sure there is sufficient air within the locker C.de-energize the windlass D.All of the above
单项选择题 According（）the report，the ship hit the wharf when berthing.
单项选择题 A vessel showing a yellow light over a white light at night is a vessel（）.
单项选择题 A message warning of a tropical storm should be sent as a(n)（）.
