While/During

Express when or while doing something: -(으)ㄹ 때 - "when" / "at the time of" • 먹을 때 = when eating • 어렸을 때 = when I was young • Can be past/present/future in meaning • 학교에 갈 때 = when going to school -(으)면서 - "while" (simultaneous actions) • 음악을 들으면서 공부해요 = I study while listening to music • Same subject doing two things at once • 먹으면서 말하지 마세요 = Don't talk while eating Key difference: • -ㄹ 때: time reference (when X happens) • -(으)면서: two simultaneous actions by same person