单项选择题
A portable foam (stored-pressure type) fire extinguisher would be most useful in combating a fire in（）.
A.generators B.oil drums C.the bridge D.combustible metals
单项选择题 A position obtained by applying only your vessel’s coures and speed to a known position is a（）.
单项选择题 A right-handed propeller will cause the survival craft to（）.
单项选择题 A sea anchor is（）.
