passive permafrost

例句：

1. 1.The region is known for its permafrost, which can be difficult to dig through.
   该地区以永久冻土闻名，挖掘起来非常困难。
2. 2. Permafrost is a geological phenomenon that occurs when the ground remains frozen for many years.
   永久冻土是一种地质现象，当地面长时间保持冻结状态时发生。
3. 3. The scientists are studying the effects of climate change on the permafrost regions.
   科学家们正在研究气候变化对永久冻土地区的影响。