问题
选择题
Without facts,we cannot form a worthwhile opinion,for we need to have factual knowledge ______ our thinking.
A．upon which to base
B．which to be based on
C．which to base on
D．to which to be based on
答案
答案：A
全句意思为：没有事实，我们就不能形成有价值的观点，因为我们的思考必须以真实的知识为基础。故选A。upon which to base our thinking是动词不定式短语作定语，该短语中介词必须放在which前。参见必背句型2。
答案：A