含三价的铬的

例句：

1. 1. Crude oil is a valuable resource that can be used for many purposes.
   原油是一种宝贵的资源，可以用于许多目的。
2. 2. The crude oil was extracted from the ground and refined into gasoline.
   原油从地下提取出来，经过提炼成为汽油。
3. 3. Crude oil prices fluctuate greatly depending on market demand and supply.
   原油价格根据市场需求和供应波动很大。