积极分子

例句：

1. 1. He is a very active member of the team.
   他是一个非常积极的团队成员。
2. 2. The company's policy encourages employees to be proactive in their work.
   公司的政策鼓励员工在工作中采取主动。
3. 3. She is an enthusiastic and active participant in the community service program.
   她是一个热情且积极参与社区服务计划的人。