What you have is correct for the most part, but they sound a little too textbookish. Also, 한국에 방문하다 should be 한국을 방문하다 or 한국도 방문하다. 방문하다 usually takes the 을/를 particle. I will list more natural ways to say those sentences. 1. If you're too loud I can't read and study. = 그렇게 시끄럽게 하(시)면 저는 책도 못 읽고 공부도 못해요. Or 그렇게 시끄럽게 하면 저는 책을 읽을 수도 (없고) 공부(를) 할 수도 없어요. (그렇게 시끄럽게 하면 = if you make so much noise. Note that 당신 is rarely used in face-to-face conversation) 2. I drank all the water and ate all the food. = 저는 물을 다 마시고 음식도 다 먹었어요. 3. I already did all of my homework and read the books. = 저는 숙제(를) 벌써 다 하고 책도 읽었어요. 4. I want to go to Japan and visit Korea. = 저는 일본에 가고 싶고 한국도 방문하고 싶어요. 5. I waited until 7 and then went home. = 저는 일곱시까지 기다리다가 집에 갔어요. In 1 through 4, the 도 particle has the function of enumerating two or more in a similar context. You can use 도 from the second item on down or for every item to emphasize the meaning. V1-다가 V2-하다 in #5 means doing something unexpected while/after doing another thing because of the circumstances. 기다리고 집에 갔어요 sounds like both actions were intentional, while -다가 in 기다리다가 집에 갔어요 implies something that was not planned but happened anyway.