单项选择题
A.red lights B.red lights and two white lights C.red lights with a white light in between D.white lights with a red light in between
A yellow signal，floating in the air from a parachute，ab...
单项选择题A yellow signal，floating in the air from a parachute，about 300 feet above the water，indicates that a submarine（）.
A.will be coming to periscope depth B.will be coming to the surface C.is on the bottom in distress D.is in distress and will try to surface
A vessel，which does not normally engage in towing opera...
单项选择题A vessel，which does not normally engage in towing operations，is towing a vessel in distress.She（）.
A.need not show the lights for a vessel engaged in towing，if it is impractical to do so B.may show the lights for a vessel not under command C.must show a yellow light above the stern light D.must show the lights for a vessel towing
A vessel sounding a fog signal of one short，one prolong...
单项选择题A vessel sounding a fog signal of one short，one prolonged，and one short blast is indicating that the vessel is（）.
A.fishing B.in distress C.at anchor D.not under command
