Without facts, a person can not form a correct opinion, for he needs to have actual knowledge his thinking .
A. on which to be based
B. on which to base
C. which to be based
D. which to base
网友回答
A. on which to be based
(答案→)B. on which to base
C. which to be based
D. which to base
解析：考查定语从句。base...on...把......建立在......的基础之上，排除C、D；base的逻辑主语是a person，与base是主谓关系，不用被动语态，排除A。故选B。