单项选择题
A.under existing visibility conditions B.under perfect visibility C.with ten miles visibility D.with fifteen miles visibility
The maximum distance at which a light may be seen under...
单项选择题The maximum distance at which a light may be seen under the existing visibility conditions is called（）.
A.nominal range B.luminous range C.charted range D.geographic range
The luminous range of a light takes into account the（）....
单项选择题The luminous range of a light takes into account the（）.
A.glare from background lighting B.existing visibility conditions C.elevation of the light D.observer's height of eye
Restricted areas at locks and dams are indicated by（）.A...
单项选择题Restricted areas at locks and dams are indicated by（）.
A.flashing red lights upstream and fixed red lights downstream B.yellow unlighted buoys C.signs and/or flashing red lights D.red daymarks upstream and green daymarks downstream
