fat coals

例句：

1. 1.The fire needs more fat coals to keep it going.
   火需要更多的硬煤来保持燃烧。
2. 2.He used to work in a coal mine before he retired.
   他在退休前曾在煤矿工作。
3. 3.The coal mine is located in the heart of the mountain range.
   煤矿位于山脉中心。