[求助]885-8-6

6.     The number of undergraduate degrees in engineering awarded by colleges and universities in the United States
                increased by more than twice from 1978 to 1985.

(A) increased by more than twice

(B) increased more than two times

(C) more than doubled

(D) was more than doubled（C）

(E) had more than doubled

答案C，但是好像没有谓语啊？D多了WAS怎么错了？

谢谢，自己顶下