单项选择题
How is a safe water mark，that can be passed close aboard on either side，painted and lighted?（）
A.Black and white stripes with an interrupted quick flashing light B.Black and red stripes with a Morse (A) light C.Black and red stripes with an interrupted quick flashing light D.Red and white stripes with a Morse (A) light
单项选择题 How does the effect known as “bank suction” act on a single-screw vessel proceeding along a narrow channel?（）
单项选择题 How does foam extinguish an oil fire?（）
单项选择题 How does an icebreaker normally free a ship which has become beset while navigating independently?（）
