He the volunteer group last year and many activities since then. A. took part in…joined

问题补充：

He the volunteer group last year and many activities since then.

A. took part in…joined B. joined…took part in C. joined…has taken part in

答案：

解析：加入某党派、某组织或某社会团体，用join；参加(群众性活动、会议等)，往往指参加者持积极态度．起一份作用。有时与join in可互换。第一空用一般过去时（last year），第二空用现在完成时（since then）