单项选择题
A.a break-glass and pull-cable system B.electrical controls on the bridge C.a mechanical arm outside the vent duct D.the heat of a fire melting the link
From your position you observe a rotating white and gre...
单项选择题From your position you observe a rotating white and green light to the north. This light is most likely（）.
A.at an airport B.on a naval mine-countermeasures vessel C.Block Island North Light D.on a vessel engaged in public safety activity
From which type of cloud can a tornado or waterspout de...
单项选择题From which type of cloud can a tornado or waterspout develop?（）
A.Nimbostratus B.Altostratus C.Cumulonimbus D.Cirrus
Freeboard is measured from the upper edge of the（）.A.bu...
单项选择题Freeboard is measured from the upper edge of the（）.
A.bulwark B.deck line C.gunwale bar D.sheer strake
