单项选择题
You are underway in thick fog.You have not determined if risk of collision exists.Which statement is true?（）
A.Your speed must be reduced to bare steerage ways B.A look-out is not required if the radar is on C.The radar should always be kept on a short-range scale D.Fog signals are only required when a vessel is detected by radar
单项选择题 Who can suggest changes to the SMS?（）
单项选择题 Which statement is TRUE when comparing cold and warm fronts?（）
单项选择题 The principal purpose of adjustment of the magnetic compass is to eliminate（）as far as possible.
