题目选项分析

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 recently discovered place that the Anasazi, ancient pueblo dwellers of New Mexico, once used the site as an observatory.

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.