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, আপনি can hear a very distinct voice from them. in the first chorus আপনি hear sooyoung, in the সেকেন্ড chorus আপনি hear sooyoung and yuri, in the bridge আপনি hear sooyoung, yuri, yoona and hyo, and in the third chorus আপনি hear hyo again.
I NEED A TIME MACHINE~~ i'm a ballad lover, hehe.. this song is perfect.. i প্রণয় it soooo much.. i heard that it was about -1C when yoona's cry scene.. yoona's acting.. JJANG!!