Without facts we can’t form a correct opinion for we need to have actual knowledgeour thin

问题补充：

Without facts，we can’t form a correct opinion，for we need to have actual knowledgeour thinking.

A. which to be based on

B. which to base on

C. on which to base

D. which to base

答案：

A. which to be based on

B. which to base on

(答案→)C. on which to base

D. which to base

解析：base A on B把A建立在B的基础上。