单项选择题
Branford reef is（）.
A.a hard sand shoal marked with a light B.completely submerged at all stages of the tide C.surrounded by rocks awash at low water spring tides D.a small，low，sandy islet surrounded by shoal water
单项选择题 An orange and white buoy with a rectangle on it displays（）.
单项选择题 An orange and white buoy marking an area where operating restrictions are in effect will be marked with which symbol? （）
单项选择题 An orange and white buoy marking a danger area will have what symbol on it?（）
