OG11 黄皮85/97请教

85 Dirt roads may evoke the bucolic simplicity of another century, but financially strained townships point out that dirt roads cost twice as much as maintaining paved roads.

(A) dirt roads cost twice as much as maintaining paved roads

(B) dirt roads cost twice as much to maintain as paved roads do

(C) maintaining dirt roads costs twice as much as paved roads do

(D) maintaining dirt roads costs twice as much as it does for paved roads

(E) to maintain dirt roads costs twice as much as for paved roads

答案是B 

对为什么不选C选项不是很理解....是不是因为maintaining dirt roads 和 paved roads不对称？   B选项为啥可以把to maintain放在as much as里面？....有没有其他类似的例句？

97. the stars, some of them at tremendous speeds, are in motion just as the planets are, yet being so far away From A...to...B

B like the planets, the stars are in motion, some of them at tremendous speeds, but they are

B选象是答案 请问, some of them at tremendous speeds, 这个结构不是很懂...为什么这里用them......

thanks a lot

顶一下....为啥没有人呢..........请教大牛...

十分感谢~