What is the light characteristic of a lighted，preferred-channel buoy? （）

单项选择题What indicates a dual purpose buoy? （）

A.Red buoy with a horizontal yellow band
B.Red and white vertically-striped buoy with a vertical yellow stripe
C.Red and white vertically-striped buoy with a red spherical topmark
D.Green buoy with a yellow square

单项选择题What describes an accurate position that is NOT based on any prior position? （）

A.Dead-reckoning position
B.Estimated position
C.Fix
D.Running fix

单项选择题Uncharted lights，fog signals and radar beacon transmissions may be（）near the station.

A.encountered
B.met
C.contacted
D.seen

单项选择题Two navigational hazards are located near to each other，but each is marked by an individual cardinal buoyage system. The buoys of one cardinal system may be identified from the other system by（）.

A.the differing light colors
B.one system having odd numbers while the other system has even numbers
C.one system using horizontal bands while the other system uses vertical stripes
D.the difference in the periods of the light

单项选择题This is（）where we shall anchor.

A.the light-house
B.the anchorage
C.the pilot station
D.the light-buoy