OG 156 (New question)

156. 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

请问 这里的C为什么不对呢？ maintaining dirt roads 可以看成是名词（主语）与 Paved roads平行，cost 是谓语与do平行。理解为费用作比较

我自己的理解是，maintaining dirt roads不等于（性质上来讲）paved roads。

对比平行是指对比对象之间的平行.

maintaining dirt roads 与paved roads是不平行的.

maintaining dirt roads 与maintaining paved roads才是平行的,但是如果这样写的话,就显得很wordy了.

谢谢 crystal  明白了

再问 OG 解释为 Choice C does the opposite: it compares the cost of maintaining dirt roads with the cost of paved roads themselves，此处的OPPOSITE怎么解释啊？COST在此句中不能做比较吗？