Sung Si Kyung collaborates with former SISTAR member, Soyou for the duet entitled “I Still”. They reveal, The duet song by SOYOU and SUNG SI KYUNG, ‘I Still’ is unveiled. SOYOU will release the pre-release song ‘I Still’ in her first solo album at 6 pm today (November 16). ‘I Still’ is a ballad duet by SOYOU and SUNG SI…