这题是省略了those吗？

frankzhiwei

1.According to a study by the Carnegie Foundation for the Advancement of Teaching, companies in the United States are providing job training and general education for nearly eight million people, about equivalent to the enrollment of the nation’s four-year colleges and universities.

(A) equivalent to the enrollment of

(B) the equivalent of those enrolled in

(C) equal to those who are enrolled in

(D) as many as the enrollment of（E）

(E) as many as are enrolled in

哪位能分析一下这个E应该是as many as （those）are enrolled in吗？  还有请问这种用法，什么时候可以省略什么时候不可以？谢谢！

futureflow

比较中，主语相同就可以省略，谓语相同也可以省略或补出助动词； 主谓都相同可以都省，仅留状语