sedimentary model of coal

例句：

1. 1. The rocks are of sedimentary origin.
   这些岩石是沉积岩。
2. 2. Sedimentary rocks are formed by the accumulation of sediment over time.
   沉积岩是由沉积物在时间推移中积累形成的。
3. 3. The study of sedimentary rocks is important for understanding Earth's history.
   研究沉积岩对于理解地球历史非常重要。