短语词组短语lean -coal 双强煤粉少油点火器Lean clean coal 瘦精煤rich -lean pulverized coal burner 浓淡型煤粉燃烧器lean coal burner 贫煤型燃烧器lean coal -fired 贫煤lean coal char 贫煤焦firing lean coal 燃烧贫煤production meager lean coal 贫瘦煤 返回 lean coal