单项选择题
A.directions B.dangers C.exclusion areas D.All of the above
A white buoy with an open-faced orange diamond on it in...
单项选择题A white buoy with an open-faced orange diamond on it indicates（）.
A.danger B.vessels are excluded from the area C.the buoy is a mooring buoy D.operating restrictions are in effect
A white buoy with a blue band is（）.A.an isolated danger...
单项选择题A white buoy with a blue band is（）.
A.an isolated danger mark B.a hydrographic data collection buoy C.a mooring buoy D.marking a restricted area
A V-shaped ripple with the point of the V pointing upst...
单项选择题A V-shaped ripple with the point of the V pointing upstream in a river may indicate a（）.
A.submerged rock，not dangerous to navigation B.sunken wreck，not dangerous to navigation C.towed-under buoy D.All of the above
