The young man，who by then admission to university，decided to do some part-time jobs to gain more practical experience．
A. gained
B. was gaining
C. has gained
D. had gained
网友回答
A. gained
B. was gaining
C. has gained
(答案→)D. had gained
解析：考查时态：句意：到那时已经获得大学录取通知书的年轻人，决定做兼职工作来获得更多的实用的经验。从句中的by then和decided to do可以判断空格处的动作发生在decided to do之前故此处用过去完成时。答案选D项。