单项选择题
A parallel of latitude other than the equator is a（）.
A.great circle B.loxodromic curve C.small circle D.gnomonic curve
单项选择题 A nun buoy will（）.
单项选择题 A mid-channel buoy，if lighted，will show a（）.
单项选择题 A line on the Earth parallel to the equator is a（）.
