单项选择题
Approaching an anchorage in fog，you hear one short，one prolonged，and one short blast in that sequence on a ship’s whistle． This indicates（）.
A.A vessel towed
B.A vessel not under command and unable to maneuver
C.A vessel anchored giving warning of her position
D.A vessel stopped dead in the water
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相关考题
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单项选择题
An occulting light is one in which（）.
A.the period of darkness exceeds the period of light
B.there is only a partial eclipse of the light
C.the periods of light and darkness are equal
D.the period of light exceeds the period of darkness -
单项选择题
An inconspicuous，partly submerged vessel or object being towed，where the length of tow is 100 meters，shall show（）.
A.yellow lights at each end
B.two red lights in a vertical line
C.a black ball
D.a diamond shape -
单项选择题
An all-round flashing yellow light may be exhibited by a(n)（）.
A.vessel not under command
B.air cushion vessel in the nondisplacement mode
C.vessel towing a submerged object
D.vessel engaged in diving operations
