먹고 and 먹어 * -고 in 먹고 is a verb conjugation that connects two verbs or verb phrases that usually(but not always) describe two distinct actions happening in sequence or in parallel. - 나 점심 먹고 바로 나갈게 = I'll have lunch first and be on my way. - 그는 학교로 가고 난 집으로 왔다 = He went to school and I returned home. * -어 and its long form -어서 connect two actions more tightly, like one is the cause or necessary step of the other. - 점심을 너무 많이 먹어(서) 졸리다. I feel drowsy because I ate too much at lunch. - 얼음을 넣어(서) 드세요. Drink it with some ice in it. * -어 is also a sentence ending. - 이 고양이는 아무 음식이나 잘 먹어. This cat eats all kinds of food very well. - 이것부터 먹어. Eat this first. (imperative sentence - no subject in the sentence)