geologic cycle

例句：

1. 1. The geologic cycle is crucial for understanding the Earth's history.
   地质周期对于理解地球历史至关重要。
2. 2.The geologic cycle has been studied for decades to understand the Earth's formation.
   地质周期已经研究了几十年，以了解地球的形成。
3. 3. The geologic cycle plays a vital role in maintaining the Earth's ecological balance.
   地质周期在维护地球生态平衡中起着至关重要的作用。