According to a 1996 survey by the National Association of College an University Business Officers, more than three times as many independent institutions of higher education charge tuition and fees of under $8,000 a year than those that charge over $16,000.

A) than those that charge

B) than are charging

C) than to charge

D) as charge

E) as those charging

The answer is E, but my choice is D. 此题考点是平行结构, as...as...应该连接的是两个句子，如果选E的话，则是句子和名词短语，不对称。请大家帮忙分析到底那个答案对，谢谢。

是收8000以下的independent institutions of higher education 和收16000以上的independent institutions of higher education 之间的比较。

不是8000和16000的比较。