白勇语法第6章语法第24练习题，高手帮助

24.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

b.dirt road 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 cost twice as much as it does for paved roads

e.to maintain dirt road costs twice as much as for paved roads

正确答案是b,但是习惯用法as much as 是不能拆分开的吧

b.dirt road cost twice as much to maintain as paved roads do

至少应该是这样吧

b.dirt road cost twice as much to maintain as paved roads to do