单项选择题
A.untrue B.impossible C.suspectful D.unimportant
The period of a lighted aid to navigation refers to the...
单项选择题The period of a lighted aid to navigation refers to the（）.
A.date of construction or establishment B.length of time between flashes of the light C.time required for the longest flash of each cycle D.time required for the light to complete each cycle
The nominal range of a light may be accurately defined ...
单项选择题The nominal range of a light may be accurately defined as the maximum distance at which a light may be seen（）.
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
