Cao Zhenyong studied politics three times, presided over the provincial examination, and took the examination four times each, which can do his best. Reading and marking can abide by the law and discipline, and will not overwhelm knowledgeable and talented people; Candidates who come to Jindian for an interview must review the examination papers one by one in advance, and their work is meticulous and there are no mistakes. Cao Zhenyong is the son of a salt merchant. His ancestors started with salt industry. A group of relatives are Yangzhou salt merchants, who have enjoyed privileges for generations and are the lifeblood of the Cao Shi family. Tao Shu, governor of Liangjiang, proposed the reform of salt policy, canceling the exclusive right of commercial salt and implementing the salt ticket law that all taxpayers can sell salt. This reform has seriously damaged the interests of Cao Zhenyong's salt merchants and their relatives. Relatives complained to Cao Zhenyong. Cao Zhenyong said, "How can there be a prime minister who starved to death?" Laughing it off, he can put aside his ancestral interests and family interests, support the reform of salt policy, and be generous and open-minded.