问题补充：
As a young man, he many social activities and later the Party.
A. took part in; joined
B. took part in ; joined in
C. joined in; took part in
D. joined; took part
答案：
(答案→)A. took part in; joined
B. took part in ; joined in
C. joined in; took part in
D. joined; took part
解析：join 表示从参加某一团体并作为其中一员,如果后接人,则表示参加某人的活动,；join in 指参加到某些人当中去做某事,这项活动往往正在进行着；take part in指参加会议或者群众性的活动等,重在说明句子的主语参加该项活动并在活动中发挥作用。句意：作为年轻人，他参加了许多社会活动，后才入了党。故选A。
