trona

例句：

1. 1. The rust on the metalsurface is a sign of age.
   金属表面的锈迹是老化的标志。
2. 2. The riverflows through the city, providing a source of waterfor the people.
   这条河流流经城市，为人们提供水源。
3. 3. Tronanois a town located in the northern partof Italy.
   特罗纳诺是一个位于意大利北部的小镇。