常見問題：
問：1. Q: What is Secret? 答： A: Secret is a South Korean girl group formed by TS Entertainment in 2009.
問：8. Q: Has Secret appeared on any variety shows? 答： A: Yes, Secret has appeared on various South Korean variety shows, such as "Invincible Youth," "Law of the Jungle," and "Hello Baby."
問：9. Q: What is the reason behind Song Ji-eun's departure from Secret? 答： A: Song Ji-eun left Secret in 2014 to focus on her solo career and acting.