A.An oxygen indicator B.A combustible gas indicator C.A combination combustible gas and oxygen indicator D.A flame safety lamp
单项选择题What is the BEST conductor of electricity?()
A.Carbon dioxide B.Distilled water C.Fresh water D.Salt water
单项选择题Upon completion of fueling a gasoline driven vessel it is necessary to().
A.keep ports,doors,windows,and hatches closed B.start engines immediately C.ventilate before starting engine D.None of the above
单项选择题There are()rats on board.
A.not B.no C.any D.none
单项选择题The vessel’s quarter is located().
A.abeam B.dead astern C.just forward of the beam on either side D.on either side of the stern
单项选择题The use of liners in riveted construction is eliminated by using().
A.lapped construction B.strapped construction C.joggled construction D.belted construction