Great as Newton was ,many of his ideas_today

Great as Newton was ,many of his ideas_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

答案：C
要点：过去完成时，被动

表示牛顿的很多想法在如今已经受到很多挑战，并被当代科学家所修定。

b