求助GWD第五套上一题语法

法兰克福来客

GWD7-Q15:

The city has proposed a number of water treatment and conservation projects the cost of which raises water bills high enough so that even environmentalists are beginning to raise alarms.



A.the cost of which raises water bills high enough so that

B.at a cost raising water bills so high that

C.at a cost which raises water bills high enough so

D.whose cost will raise water bills so high that

E.whose cost will raise water bills high enough so that


正确答案选D,不是很理解，有哪位大牛帮忙解释一下？谢谢啦！

kingstorm666

要么是enough to..要么是so that.两个不能混着一起用。   B中的raising做分词修饰了前面的名词cost是错误的。
whose可以表示人和物体的所有形式。

法兰克福来客

明白了，谢谢啊