单项选择题
A.sunset B.civil twilight C.nautical twilight D.astronomical twilight
Elongation becomes zero at（）.A.oppositionB.west quadrat...
单项选择题Elongation becomes zero at（）.
A.opposition B.west quadrature C.apogee D.inferior conjunction
During one synodic rotation，a body makes one complete t...
单项选择题During one synodic rotation，a body makes one complete turn relative to the（）.
A.Earth B.Sun C.stars D.vernal equinox
Diurnal aberration is due to（）.A.motion of the Earth in...
单项选择题Diurnal aberration is due to（）.
A.motion of the Earth in its orbit B.rotation of the Earth on its axis C.the body's orbital motion during the time required for its light to reach the Earth D.a false horizon
