drip stone

例句：

1. 1. The river flows over the dropstone, creating a beautiful pattern in the water.
   河水流过滴水石，在水面上形成了美丽的图案。
2. 2. The dropstone is a unique feature of this area, attracting many visitors.
   滴水石是这个地区的独特特征，吸引了许多游客。
3. 3. The dropstone has been used for centuries as a natural filtration system.
   滴水石被用作自然过滤系统已有数百年的历史。