When television was first introduced, the extent it would affect society could not have been foreseen.
A. of which
B. of what
C. to which
D. in which
网友回答
A. of which
B. of what
(答案→)C. to which
D. in which
解析：考查定语从句：句意：当电视一开始被引入的时候，它对世界会有什么影响程度不可能被预见的，考的是“介词关系代词”中介词的选择问题。To …extent意思为“在…程度上”。所以用to which引导定语从句，选C。