单项选择题
A pilot chart does NOT contain information about （）.
A.average wind conditions B.tidal currents C.magnetic variation D.average limits of field ice
单项选择题 A petroleum liquid has a flash point of 85°F. This is a grade （）.
单项选择题 A negative metacentric height （）.
单项选择题 A navigator fixing a vessel’s position by radar （）.
