double twice在G中的考点？？

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

这题答案是C　如何解释？？　　有没有人总结下double 和twice 的用法?

Choice
A is faulty because an adverb such as twice cannot function as an object
of the preposition by. B distorts the sentence's meaning, stating that
the number of engineering degrees conferred increased on more than two distinct
occasions. D's passive verb was ... doubled suggests without warrant
that some unnamed agent increased the number of engineering degrees. The past
perfect tense in E, had... doubled, is inappropriate unless the increase
in engineering degrees is specifically being viewed as having occurred further
back in the past than some subsequent event. Choice C is best.

大全的解释在哪可以找到？？

double 和twice是不可以被动的，DE除去，一般看到double主动+sth就得有些好感。

A。多了By，而且increase是多余了.

B.我感觉后面少了比较名词。

很多题目做下来，有主动double的基本就是正确项了。