듣다 and 출석하다 - 듣다 - 1) hear, listen, 2) acquiesce and follow, 3) be informed (of some news), 4) work or function (as expected). - 출석하다 - be present (at a lecture, meeting, etc); attend. ('출석' literally means going to/taking one's seat). 듣다 can mean 강의를 듣다, often used in the sense of "to attend" or "to take", but only in an academic context. As you can see in the above definitions, the two words are quite different. They are seldom interchangeable. Outside of a school setting, 참석하다 can mean "to attend" as well. - 너 교양 강좌 A1 들을 거야? - Are you going to take Liberal Arts A1? - 난 오늘 세미나 듣기로 했어 - I decided to sit in on the seminar today. - 오늘 출석하지 않은 [결석한] 사람은 감점을 받을 겁니다 - Those not present [absent] today will receive a deduction. - 나는 친구의 장례식에 참석했다 [갔다] = I attended [went to] my friend's funeral. - 이번 이사회에는 11명이 참석했다 = Eleven members attended the board meeting this time.

"수업을 듣다" means "take a lesson" "수업에 출석하다" means "attend a lesson"