The professor could hardly find sufficient grounds ________ his arguments in favor of the new theory．
A.on which to base
B.which to base on
C.to base on
D.to be based on
网友回答
A解析题意为“教授几乎找不到支持这一新理论的充分理由”。根据题意，题中的professor是想将自己的argument建立在sufficient grounds之上，即to base his arguments on these sufficient grounds。因此，关系代词which指代先行词grounds，作介词on的宾语。