[求助]GWD一题 求解

Q3:

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.

1. each a roof of poles and arrowweed
2. each a roof of poles and arrowweed that are being
3. with each being a roof of poles and arrowweed
4. with roofs of poles and arrowweed to be
5. with roofs of poles and arrowweed that are

我下的版本上，选A，可是我记得 each a 没这个用法吧？请牛牛指点

谢谢

一般独立主格(n.＋n./-ed/-ing/介词短语/adj短语)与主句形成松散的逻辑关系

with型独立主格(with n.+ -ed/-ing/adj/介词短语)与主句形成紧密的逻辑关系
        （前两种就差一个with）

     （注：因为是紧密的逻辑关系，所以是修饰就近的谓语动词，注意不是非谓语动词，也不一定是主句动词）

each型独立主格(复数名词结尾,each+介词短语/adj短语/-ed/-ing)强调句尾名词（each后可以加with,as等介词）

解释的很道理，我排除法做的。。。A

each型独立主格(复数名词结尾,each+介词短语/adj短语/-ed/-ing)强调句尾名词（each后可以加with,as等介词）

再举个例子吧，请ls