On open waters，a power-driven vessel shall keep out of the way of a（）.

单项选择题It has often been stressed in the Courts that the look-out man should，preferably，be stationed forward，unless weather conditions make this（）.

A.possible
B.practicable
C.impossible
D.probably

单项选择题In the daytime，you see a large sailing vessel on the beam. You know that she is also propelled by machinery if she shows（）.

A.a basket
B.a black ball
C.a black cone
D.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