strengite

例句：

1. 1. The construction site is surrounded by hard stone walls.
   施工现场被坚硬的石头墙包围。
2. 2. Granite is a popular choice for flooring materials due to its durability and aesthetic appeal.
   由于其耐用性和美观性，花岗岩是地板材料的热门选择。
3. 3. The ancient city was built on solid rock, making it difficult to excavate.
   这座古城建在坚硬的岩石上，这使得挖掘工作变得困难。