V-(으)면서

while

Explanation

-(으)면서 indicates that the actions of the first and second verbs occur simultaneously. It means 'while' in English. When the verb stem ends in a vowel or ㄹ, -면서 is used, and when it ends in a consonant, -으면서 is used.

Details

The subjects of both clauses are the same. That is, they must be the same person.

민수 씨는 노래를 하면서 재준 씨는 피아노콜 칩니다. ✕
→(민수 씨는) 노래를 하면서 (민수 씨는) 피아노를 칩니다. ✓
(Min-su) plays the piano while he (Min-su) sings.
→민수 씨가 노래를 하는 동안 재준 씨는 피아노를 칩니다. ✓
While Hayeong sings, Jaejun plays the piano.

When the subjects of the two verbs are different, -동안 is used.

동생이 청소를 하는 동안 언니는 빨래를 했습니다.
While my little brother/sister was cleaning the house, my older sister did the laundry.

Past and future tense endings are not added to the verb preceding -(으)면서. It is always written in present tense.

어제 민수 씨는노래를 했으면서 피아노를 쳤습니다. ✕
→어제 민수 씨는 노래를 하면서 피아노를 쳤습니다. ✓
Yesterday, Min-su sang while she played the piano.

Kimchi Reader

Indicates that two or more actions are happening at the same time.