单项选择题
A buoy marking a wreck will show a(n)（）.
A.white light FL (2) and a topmark of 2 black spheres B.occulting green light and may be lettered C.yellow light and will be numbered D.continuous quick white light and may be numbered
单项选择题 A buoy having red and green horizontal bands would have a light characteristic of（）.
单项选择题 A bold reef is a reef（）.
单项选择题 （）means the curve on the earth’s surface which cuts all the meridians at the same angle.
