complex cycle

例句：

1. 1. The complex cycle of life is a fascinating subject to study.
   生命的复杂循环是一个引人入胜的研究主题。
2. 2. In the complex cycle of global warming, each country plays a unique role.
   在全球变暖的复杂循环中，每个国家都扮演着独特的角色。
3. 3. The company's complex cycle of operations and maintenance has been well-documented.
   该公司复杂的操作和维护周期已被详细记录。