单项选择题
A line on the Earth parallel to the equator is a（）.
A.gnomonic curve B.small circle C.meridian D.great circle
单项选择题 A line of position formed by sighting two charted objects in line is called a(n)（）.
单项选择题 A lighthouse can be identified by its（）.
单项选择题 A lighted preferred-channel buoy may show a（）.
