单项选择题
How does foam extinguish an oil fire?（）
A.By cooling the oil below the ignition temperature B.By removing the fuel source from the fire C.By excluding the oxygen from the fire D.By increasing the weight of the oil
单项选择题 How does an icebreaker normally free a ship which has become beset while navigating independently?（）
单项选择题 How does a vessel’s rate of turn change when entering shallow water?（）
单项选择题 How does a coast radio station communicating by HF radio normally identify itself?（）
