I know him ______ a good football player while in college

I know him ______ a good football player while in college

A.to have been

B.to be

C.was

D.had been

答案及解析： A

解析：

考查时态。句意“我知道她在大学时是一个出色的足球运动员。”know和be有先后关系，故用完成时。故选A。