常見問題：
問：4. Q: What was Secret's debut song? 答： A: Secret's debut song was "I Want You Back," released in 2009.
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.
問：7. Q: Has Secret released any albums? 答： A: Yes, Secret has released several albums, including "Moving in Secret," "Secret Time of the Day," and "Letter from Secret."