单项选择题
A.on the prime vertical
B.on the celestial horizon
C.at lower transit
D.on the Greenwich meridian
单项选择题 A lashing used to secure two barges side by side，lashed in an "X" fashion，is called a （）.
单项选择题 A lashing used to secure two barges side by side，lashed in an "X" fashion，is called a （）.
单项选择题 Information on the operating times and characteristics of foreign radiobeacons can be found in which publication? （）.