Question

帮我看一个非谓语动词选择题

6. The professor could hardly find sufficient grounds _____ his 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 为什么不能A呢？

Answer 1

6. The professor could hardly find sufficient grounds _____ his 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 为什么不能A呢？
答：首先你将这题作为一个句型背下来.
on which to base sth. 相当于定语从句on which you can base sth.
可以看作类似于疑问不定式的之类的东西。我们知道疑问不定式可以作宾语，如：I don't know what to do.= I don't know what I can do.
同理，介词+which +to do sth. =介词+which sb. can/could do sth. 只不过是作后置定语的。
本句=The professor could hardly find sufficient grounds on which he could base his arguments in favor of the new theory.
那教授很难找到足够的支撑他的有利于这个新理论的基础。
定语从句还原就是：He could base his arguments in favor of the new theory on these grounds.
是将其arguments 建立在这些个grounds上。
而如果选A，则是一个不定式的被动式作后置定语，相当于：。。。grounds which would be based on his arguments..., 也就是说，这些grounds 是被建立在其arguments之上的。这就不符合逻辑上。
我们是将house建在地面上：to base a house on the ground, 也就是说the house is based on the ground 而不是the ground is based on the house
明白了吗？

Answer 2

如果你选A，
Find是谓语，be base on 也是谓语，那这个句子里面岂不是有两个谓语？
这样子句子中如果没有连接词，肯定是病句。一下子就排除了。

Answer 3

A完全讲不通。勉强用被动语态，也无法连接后面已提供的句子。

Answer 4

因为题中已经有谓语find，不能再出现谓语，所以A不对

Answer 5

find doing 是不是