东方神起RISING SUN 的歌词中是否有"UKNOW WHY"啊

是的，不过是YOU KNOW WHY而不是UKNOW WHY。
以下是给你参考的证据:

这是RISING SUN的韩文版歌词。

YC=micky yoochun
CM=max chamgmin
YH=u-know yunho
JS=xiah junsu
JJ=hero jaejung

[YC] Now, I cry under my skin.. haneureul hyanghae gan nah eui noonmoolro mandeun beega
daejee eh naeryuhdo sehwureh bagheen nae apeumeul sseesuhgado

[CM] No! [YH] yongsuh naegehn juldaejugeen sachee
[CM] No! [YH] pyojuk ubsuh nalagan geereul eeleun boonno
[CM] No! [YH] nah, meeryun gateun malro geedo haneun sogjwee
[CM] No! [YH] Here I go, Come back!

[JS] heemeul eeruhbuhreen nalgae jaega dweeuh bureel guman gateun nardeul
beesangha reeran ggoom eui papyun deulro maeun nah eui achimen banjjag eemee ubneundeh

[JJ] jeenseeleun noogoo rado gago eeneun guh hajeeman boyuhjoon ulgoolen gujeebooneengur
youngwuneh namgyujeen nareul chaneunga?

*[ALL] nareul darmah gaseum aneh gadeuk cha kuhjyuhganeun Innocent <