single coal的用法和样例：
例句
- The combustion characteristic of macerals from four types of coal are investigated by means of thermogravimetry.
本文用热天平研究了四种煤的显微组分富集物的燃烧特性。 - Two raw coals from Yueliangtian and Kaili coal mines in Guizhou Province were extracted with dichloromethane separately.
摘要用二氯甲烷对贵州月亮田和凯里两种煤样进行了索氏萃取，并采用柱色谱对萃取物进行了族组分分离。
