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：2. Q: How many members are there in Secret? 答： A: Secret originally had five members, but now consists of only four members after Song Ji-eun's departure.
問：6. Q: What is Secret's most popular song? 答： A: Secret's most popular song is "Poison," which was released in 2014 and became a huge hit in South Korea.