单项选择题
Buoys which mark dredging areas are painted（）.
A.black B.yellow C.green D.red
单项选择题 Buoys are marked with reflective material to assist in their detection by searchlight. Which statement is TRUE? （）
单项选择题 Branford reef is（）.
单项选择题 An orange and white buoy with a rectangle on it displays（）.
