1. (~하)구요=(~하)고요 When you want to mention something(certain behavior, action, condition etc.) one by one, you can use it. It is a informal expression. (예시) 동생은 공부하구요, 언니는 음악 듣구요, 나는 영화보고 있어요. (translation) My younger sister is studying, elder sister is listening to music and I'm watching a movie. 2. 라구요=라고요 When you want to remind someone what was already said to him/her, you can use it as a declarative or interrogative expression. (예시) 공부하라구요. (translation) (A) said to (B) B should study I said to you you should study / My mother said to me I should study / I said to my brother he should study / etc. (예시) 공부하라구요? (translation) (A) said to (B) B should study ? Did You say to me I should study ? / Did he say to you you should study ? / etc. Sometimes you can use it to stress a citation. (예시) 아버지가 말했어요. 아침에 일찍 일어나라구요. (translation) My father said (to me) I should get up early in the morning. 3. ~하는구만 / ~구만 Actually it is kind of a exclamotory sentence. Sometimes it suggests a unexpected fact. (예시) 한국말 아주 잘 하는구만 (translation) You speak Korean very well. (Actually I doubted you can do that) (예시) 이 영화 엄청 슬프구만. (translation) The movie is so sad. (Actually I didn't imagine it would be) 4. ~하는구나 / ~구나 It is kind of a exclamotory sentence. Sometimes it suggests a unexpected fact. (예시) 한국말 아주 잘 하는구나. (translation) You speak Korean very well. (I didn't know you can do that) (예시) 이 영화 엄청 슬프구나. (translation) The movie is so sad. (I didn't know it would be)