For protection from the summer sun, the Mojave lived in open-sided, flat-topped dwellings known as shades, each a roof of poles and arrowweed supported by posts set in a rectangle.
5. For protection from the summer sun, the Mojave lived in open-sided, flat-topped dwellings known as shades, each a roof of poles and arrowweed supported by posts set in a rectangle. (A) each a roof of poles and arrowweed (B) each a roof of poles and arrowweed that are being (C) with each being a roof of poles and arrowweed (D) with roofs of poles and arrowweed to be (E) with roofs of poles and arrowweed that are
each在这做什么啊?是不是省略了with 全句为each with a roof of 。。。。。。,修饰shades,这样理解对吗?