GWD13-29？？

falchion

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 a roof of poles and arrowweed

each a roof of poles and arrowweed that are being

with each being a roof of poles and arrowweed

with roofs of poles and arrowweed to be

with roofs of poles and arrowweed that are

Answer: A

NN请帮忙将此句的成分划分一下，我实在看不懂为什么选A，多谢了

  

mariezhu

The mojave lived in ....dwellings, each {<a roof of (poles and arrowweed)> supported by posts ...}

each a roof of ... : absolute phrase

falchion

got it,thx