VOA慢速英语:汉堡王推新款汉堡 使用减少甲烷排放的牛肉

chain –n. a business with many different stores, restaurants or hotels, for example, that have a similar appearance and provide the same products or services

vulgar –adj. something that does not show good manners, good taste or good behavior

digestion –n. the process within the body that breaks down food into energy and needed substances

emission –n. the act of producing or sending out something (such as energy or gas) from a source