問題詳情
9. The period of incomplete darkness when the upper limb of the sun is below the visible horizon, and the center of the sun is not more than 6° below the celestial horizon. It is:
(A) Civil twilight
(B) Nautical twilight
(C) Astronomical twilight
(D) Global Horizon twilight
參考答案
答案：A
難度：適中0.55
書單：沒有書單，新增