29.  There are hopeful signs that we are shifting away from our heavy reliance on fossil fuels: more than ten times as much energy is generated through wind power now than it was in 1990

A) generated through wind power now than it was

B) generated through wind power now as it was

C) generated through wind power now as was the case

D) now generated through wind power as it was

E) now generated through wind power than was the case

A: than和as不平行

B: it 不能指代energy，

C: the case指代energy

D: it 不能指代energy 

E: than和as不平行

B.C的区别在哪里呢？为何it不能指代energy，而且其前面只有一个单数名词。？？？

同问同问

而且不明白为什么it 不能只待energy？

"it" can not be used in this context b/c the energy prouduced now is no longer the same energy produced before. Otherwise, B and D would have been correct. If you still remember the OG question about earthquake of the East and the West, you will get the feel.

正确答案是B还是C？