穴居人

例句：

1. 1. The cave dwellers have adapted to the harsh conditions in the underground world.
   洞穴居民已经适应了地下世界的恶劣条件。
2. 2. The cave dwellers are known for their unique adaptations to life underground.
   洞穴居民因其对地下生活的独到适应而闻名。
3. 3. The cave dwellers use tools made from stone and bone to survive in their underground home.
   洞穴居民使用石头和骨头制成的工具来在他们的地下家园中生存。