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
相关考题
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单项选择题
On cargo booms，preventers are（）.
A.auxiliary guys
B.extra fair leads
C.steel bands
D.stops -
单项选择题
Mechanical gearing of deck machinery such as the windlass or boat hoists should（）.
A.be open to view so，if a foreign object gets in the gearing，the operator can immediately stop the machinery
B.have a guard over the gearing
C.be painted a contrasting color from the base color in order to call attention to the gearing
D.not be operated if there is any crew within 10 feet of the machinery -
单项选择题
Lines or gear NOT in use should be（）.
A.conspicuously marked
B.stowed anywhere
C.left on deck
D.secured or stowed out of the way
