煤焦油

例句：

1. 1. The coal tar is used inthe production of various chemicals.
   煤焦油用于生产各种化学品。
2. 2. The pitch is abyproduct of the coal industry.
   煤焦油是煤炭工业的副产品。
3. 3. Coal tar is also known as pitch.
   煤焦油也被称为焦油。