相关考题
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单项选择题
On which type davit does the davit head stay at the same height?（）
A.Radial
B.Sheath-screw
C.Quadrantal
D.Gravity -
单项选择题
On what type of pump would you find an impeller?（）
A.Centrifugal
B.Gear
C.Piston
D.Vane -
单项选择题
On navigational aids，what does the light characteristic Fl(2+1) mean?（）
A.A flashing light combined with a fixed light of greater brightness
B.Light flashes combined in groups，with a different number of flashes in each group
C.A light showing groups of two or more flashes at regular intervals
D.A fixed light varied at regular intervals by groups of two or more flashes of greater brightness
