Hello One use is when you want someone to do something (imperative command) 좀 is used to make a positive sentence more polite, similar to please. 불고기를 좀 먹어 주세요 Please eat Bulgogi 말다 give the sentence a negative meaning, don't do. 먹지 말아 주세요! Please don't eat! However Koreans usually shorten it by putting 말다 as the ending. 먹어 마세요! Don't eat! be aware of the irregular conjugating rule for ㄹ. 감사합니다! :)