单项选择题
A lateral system buoy displaying a quick light（）.
A.should be passed close aboard on either side B.indicates that special caution is required C.is used at a channel bifurcation or junction D.is painted with red and white vertical stripes
单项选择题 A great circle track provides the maximum saving in distance on（）.
单项选择题 A gnomonic projection is based on a(n)（）.
单项选择题 （）refers to the angle between true North and the heading line of the ship.
