煤球

例句：

1. 1. The coal ball was used as a fuel for the machine.
   这个煤炭球被用作机器的燃料。
2. 2. The coal clump is too heavy to carry.
   这个煤炭块太重了，搬不动。
3. 3. Coal balls are often used in industrial processes.
   煤炭球通常用于工业过程中。