Ammonia, coal tar and coke are all by-products obtained in the manufacture of coal gas.
Ammonia, coal tar and coke are all by-products obtained in the manufacture of coal gas.
氨气、煤焦油、焦煤都是煤气生产过程中的副产品.
Ammonia, coal tar and coke are all by-products obtained in the manufacture of coal gas.
氨气、煤焦油、焦煤都是煤气生产过程中的副产品.