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.
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.
each 指的是 each shade,後面接的 a roof of poles and arrowwood (題目打錯字母了)supported by posts set in a rectangle 整個片語是形容each shade,意思大致是"由支柱撐起來的,使用竿子和arrowwood(某種木頭,但我不知道中文是什麼)、呈現矩形的屋頂"。