According to a 1996 survey by the National Association of College and 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.
According to a 1996 survey by the National Association of College andUniversity Business Officers, more than three times as many independentinstitutions 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
答案是E 为什么不是D呢?as many institutions charge ... as (those who) charge over ... 这样不更简洁吗?