The professor could hardly find sufficient grounds( ) his arguments in favor of the new theory.

Question

A.to be based on
B.to base on
C.which to base on
D.on which to base
选D。为什么？可以分析一下句子结构吗？还有这个句子是什么意思？

Answer 1

定语从句.
这里grounds 是先行词
which 是关系代词
由于base...on...是词组
所以这里就把介词提前组成了
on which to base
为什么这里是to base呢
因为前面的find
词组是find...to do...这里是find sufficient grounds to ...

Answer 2

theory on 关于……的理论
所以要用介词on

所以用D

Answer 3

你的问题挺好解决的.楼上两位都错了 或不完全对本回答被提问者采纳