지금 자야 되는데 할 게 많아서 이따가 잘거예요 = I should sleep now, but I have a lot of things to do, so I'll sleep later. 할 = 하다 + ㄹ = future tense "to do" 게 = 것 + 이 (subject marker) = "thing(s)" 많아서 = 많다 -> 많아 + 서 = "many" + "so" 배가 고프다 -> 배가 고파 means the same thing as 배고프다 -> 배고파 (I'm hungry/to be hungry etc.). There's two ways to say it, that's all :). 배 means stomach/tummy, 가 is just the subject marker and 고프다/고파 is the adjective. So in a way it just makes it clear that it's your stomach that's hungry haha. Basically 오늘은 배가 너무 고파서 집에 오자마자 밥을 먹었어요 = I was really hungry today, so as soon as I got home, I ate something/food.