单项选择题
Which position includes the effects of wind and current（）.
A.Dead reckoning position B.Leeway position C.Estimated position D.Set position
单项选择题 Which of the following are data layer categories to be displayed on ECDIS（）．
单项选择题 Which buoy will NOT display white retro reflective material（）.
单项选择题 When using horizontal sextant angles of three objects to fix your position，an indeterminate position will result in which situation（）.
