A.Running fixB.FixC.Dead-reckoning positionD.Estimated ……

单项选择题Which statement concerning current is TRUE（）.

A.Current can be determined by measuring the direction and distance between simultaneous EP and DR positions
B.The drift of the current should be averaged out on a one hour basis
C.After the current is determined，it should not be used for further plotting because it is an unknown variable
D.The distance between a simultaneous DR position and fix is equal to the drift of the current

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（）．

A.ECDIS warnings and messages
B.Hydrographic Office data
C.Notice to Mariners information
D.All of the above

单项选择题Which buoy will NOT display white retro reflective material（）.

A.Safe water mark
B.Isolated danger mark
C.Preferred channel mark
D.Daymark of no lateral significance

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（）.

A.The objects lie in a straight line
B.The vessel is inside of a triangle formed by the objects
C.The vessel is outside of a triangle formed by the objects
D.A circle will pass through your position and the three objects