"수영 잘 해?" Are you good at swimming? "수영 잘 해 요?" (... 요 polite expression) "아니, 전혀 못해." NO, I can't swim company. "아니, 전혀 못해 요."
전혀 Negative
"이니, 잘 못해 요." NO, I'M NOT Good At Swimming. (But I can)
잘 해 [자래] 못해 [모태] 전혀 [저녀]
