stone sand

例句：

1. 1. The beach is covered in smooth stones and soft sand.
   海滩上覆盖着光滑的石头和柔软的沙子。
2. 2.The river flows through a landscape of rocks and sand.
   河流穿过岩石和沙地的景观。
3. 3.Stones and sand are often used to build walls and foundations.
   石头和沙子经常被用来建造墙壁和地基。