GWD-10-Q3
For protection from thesummer sun, the Mojave lived in open-sided, flat-topped dwellings known asshades, each a roof of poles and arrow
weed supported by posts setin 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


A的语法如何解释？我倒觉得E比较好，请高手帮忙解答一下，谢谢！

虽然不算是高手，不过这道题我见过，所以借用前人的只是说两句。
这里是each引导的特殊独立主格，这种独立主格要求each前面不能加with，each指代前面复数名词中的每一个。所以CDE排除
A是省略了being的，出于简洁原则。B的that are being是典型的冗余
C选项可以看作是是A的补全形式，不过由于是each引导，所以要去掉with，简洁去掉being，就成了A

明白了，谢谢！