题目选项分析

The Anasazi settlements at Chaco Canyon were built on a spectacular scale of more than 75 carefully engineered structures of up to 600 rooms each had been connected by a complex regional system of roads.

The Anasazi settlements at Chaco Canyon were built on a spectacular scale, with more than 75 carefully engineered structures, of up to 600 rooms each, connected by a complex regional system of roads.