单项选择题
As observed from the Earth，the angle between lines from the Earth to the Sun and the Earth to an inferior planet is known as（）.
A.elongation B.conjunction C.opposition D.quadrature
单项选择题 Apparent altitude is sextant altitude corrected for（）.
单项选择题 An amplitude of the Sun in high latitudes（）.
单项选择题 Altair is found in what constellation?（）
