What books should I read to supplement my legal knowledge?

My suggestion is that if you are interested in learning, you can first read Principles of Civil Law edited by Zhang Junhao. If you want to know the basic knowledge of law in case of emergency, you might as well study law. First look at the administrative punishment law, the administrative reconsideration law and the administrative procedure law. If you can't grasp the gist, you can refer to The Theory of New Administrative Law (Ying Songnian), which is mainly written by people with administrative experience and is of great reference significance.