actually, they do sing, it look me time to figure it out, but the 4 main dancers sing in the chorus and in the bridge, आप can hear a very distinct voice from them. in the first chorus आप hear sooyoung, in the सेकंड chorus आप hear sooyoung and yuri, in the bridge आप hear sooyoung, yuri, yoona and hyo, and in the third chorus आप hear hyo again.
I NEED A TIME MACHINE~~ i'm a ballad lover, hehe.. this song is perfect.. i प्यार it soooo much.. i heard that it was about -1C when yoona's cry scene.. yoona's acting.. JJANG!!