问题
选择题
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．have challenged
C．are challenging
D．have been challenged
答案
答案：D
challenge同ideas之间存在被动关系。句子表“当年牛顿的许多想法受到了质疑”之意。