求英语语法大神!Great as Newton was, many of his ideas___C___today and ar_英语解答

求英语语法大神!
Great as Newton was, many of his ideas___C___today and are being modified by the work of scientists of our time.
A.are to challenge
B.may be challenged
C.have been challenged
D.are challenging
正确答案是C,我选了D,求解释啊

人气：318 ℃　时间：2020-02-06 01:11:29

解答

首先弄明白challenge的意思,动词：挑战,质疑；名词：挑战.在此作动词：质问.
选项分析：BC均为被动,C为现在完成时；AD是主动,A表将来时,B表现在进行时；
many of his ideas：他许多的想法,应该是他的想法被质疑,而不是他的想法质疑,排除AD；
他的许多想法已经被质疑,所以才被改进modified,所以选C