stone ice

例句：

1. 1. The ancient city is surrounded by a large stone wall.
   这个古老的城市被一座巨大的石墙包围。
2. 2. The builders used stones to build the walls of the castle.
   建造者用石头建造了城堡的墙壁。
3. 3. The old man was digging in the garden with a stone pickaxe.
   那个老人正在花园里用石镐挖土。