单项选择题
The compass rose on a nautical chart indicates both variation and （）.
A.deviation B.annual rate of variation change C.precession D.compass error
单项选择题 The charts sold are of （）.
单项选择题 The chart symbol indicating that the bottom is coral is （）.
单项选择题 The chart of a beach area shows a very flat slope to the underwater beach bottom. What type of breakers can be expected when trying to land a boat on this beach? （）
