A.a basketB.a black ballC.a black coneD.two black cones……

单项选择题In restricted visibility the speed of a vessel without operational radar may be（）enable effective avoiding action to be taken on sighting another ship.

A.too low to
B.too high to
C.too high for
D.too low for

单项选择题In restricted visibility a towed vessel must sound a fog signal when it is（）.

A.the last vessel in the tow
B.the last vessel in the tow and it is carrying a crew
C.manned，regardless of its position in the tow
D.None of the above are correct

单项选择题In reduced visibility，you hear two prolonged blasts of a whistle. This signal is sounded by a （）.

A.power-driven vessel dead in the water
B.sailing vessel on the port tack
C.vessel not under command
D.vessel fishing with nets

单项选择题In order to maintain speed while changing course from a close reach to a broad reach，the sails should be（）.

A.lowered
B.reefed
C.hauled in
D.eased out

单项选择题In order for a vessel to be engaged in fishing she must be（）.

A.underway
B.using gear which extends more than 50 meters outboard
C.using a seine of some type
D.using gear which restricts her maneuverability