https://blog.gongquiz.com/2022/11/24/one-stop-guide-to-korean-particles-%ec%9d%80-%eb%8a%94-%ec%9d%b4-%ea%b0%80-subject-topic-markers-%e3%88%9b/
One-Stop Guide to Korean Particles - 은/는/이/가 (Subject & Topic Markers) ㈛