单项选择题
A.at elongation angles near 180°
B.from quadrature to opposition
C.at conjunction
D.at opposition
单项选择题 It is difficult to determine which limb of the Moon is fully illuminated（）.
单项选择题 In working out a local apparent noon sight for your latitude，you subtract the Ho from 90°. The 90°represents the angular distance from（）.
单项选择题 In the navigational triangle，the angle at the elevated pole is the（）.