zài / zhè / jù / huà / lǐ / lǎo / huáng / niú / shì / zhuǎn / yì / yòng / fǎ / zhǐ / qín / láo / néng / gàn / de / rén在这句话里,“老黄牛”是转义用法,指勤劳能干的人。In this sentence, “老黄牛” is used figuratively to refer to a hardworking and capable person.