A.purpleB.orangeC.blueD.yellowThe four standard light c……

单项选择题The equator is（）.

A.the primary great circle of the Earth perpendicular to the axis
B.the line to which all celestial observations are reduced
C.the line from which a celestial body's altitude is measured
D.All of the above

单项选择题Restricted areas at locks and dams are indicated by（）.

A.Flashing red lights upstream and fixed red lights downstream
B.Yellow unlighted buoys
C.Signs and/or flashing red lights
D.Red daymarks upstream and green daymarks downstream

单项选择题On a chart，the characteristic of the light on a lighthouse is shown as flashing white with a red sector.The red sector（）.

A.Indicates the limits of the navigable channel
B.Indicates a danger area
C.Is used to identify the characteristics of the light
D.Serves no significant purpose

单项选择题In very high latitudes，the most practical chart projection is the（）.

A.Mercator
B.Gnomonic
C.Azimuthal
D.Lambert conformal

单项选择题How would you pass a red buoy in the maritime buoyage system“A” （）.

A.keep the buoy on the vessel's starboard side when approaching a port and on the vessel's port side when leaving
B.keep the buoy on the vessel's port side when approaching a port and on the vessel's starboard side when leaving
C.keep the buoy on the vessel's starboard side when approaching and leaving
D.keep the buoy on the vessel's port side when approaching and leaving