题目选项分析

At a recently discovered site once used as an observatory by the Anasazi, ancient pueblo dwellers of New Mexico, patterns of light and shadow were employed to establish the precise limits of the positions of the Sun and Moon over a nineteen-year cycle.

Patterns of light and shadow were employed to establish the precise limits of the positions of the Sun and Moon over a nineteen-year cycle at a site that was recently discovered and was once used by the Anasazi, ancient pueblo dwellers of New Mexico.