role in cycle of matter

例句：

1. 1. The role of a leader is to inspire and guide others.
   领导者的角色是激励和引导他人。
2. 2. He played the role of a hero in the movie.
   他在电影中扮演了英雄的角色。
3. 3. The new president has taken on a significant role in the company.
   新任总裁在公司中承担了重要的角色。