"The child drank all the milk."
Translation:아이가 우유를 다 마셨어요.
아무 is used like "any" in English, like "anyone", whereas 다 is used to mean all of something, placed after the noun.
Here's an example: 화장실 아무대나 있어요? "Is there a bathroom anywhere?"
versus: 밥을 다 먹었습니다. "I ate all of the rice/food"