阿摩線上測驗
10. The period of incompleted 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
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統計： A(329), B(81), C(34), D(30), E(0) #1444703
統計： A(329), B(81), C(34), D(30), E(0) #1444703
