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：4. Q: What was Secret's debut song?
答： A: Secret's debut song was "I Want You Back," released in 2009.
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.
