The professor could hardil find sufficient grounds _____hia arguments in favor of the new theory.

题目

The professor could hardil find sufficient  grounds _____hia arguments in favor of the new theory.
A.to be based on                  B.to base on                     C.which to base on          D.on which to base
 
 答案：D为什么     说思路、

答案

这是 base A on B 句型 以乙作 甲的基础 base his arguments on sufficient grounds 以足够大理由作辩论 的根据
如果选B 的 话 应该是The professor could hardly find sufficient grounds to base his arguments on in favor of the new theory.
这是 动词不定式 作定语 与所修饰词 是动宾关系
但是 本句 on的位置不对
所以 答案是 D 其实也是不定式作定语 只不过 前面加了on which 相当于一个定语从句
=on which he based his arguments