Well, I can't teach you a detailed korean grammar. It is very hard for me to explain, but I will do my best. 음(름,ㅁ) is usually used like this : 노래를 부름(singing a song) We usually don't say 음(름,ㅁ) when we are talking with someone. Because you can't keep talking when you say 음(름,ㅁ), BUT young people often say 음(름,ㅁ) It is a kind of noun, but young people use it like as verbs. Ex) 나 어제 친구를 만남, 그리고 노래방에 감, 그리고 집에 감. 넌 뭐했냐? (I met my friend yesterday, we went to karaoke. Then, I went home. What did you do yesterday?) -기 : 노래 부르기(노래 부르기) (you can say without '를') Usually, -기 has more words after itself. or you can only use it. EX) : 1.내 취미는 노래 부르기이다. (My hobby is to sing a song.) Finally. -는 것 is very similar to -기. EX) 내 취미는 노래를 부르는 것이다. (It is very similar to above one.) you can use both -는 것 and -기 when you say like above examples. If you have mroe questions, feel free to ask me :D

Thank you so much! ^^

Read these two helpful pages: http://www.howtostudykorean.com/unit-2-lower-intermediate-korean-grammar/unit-2-lessons-26-33/lesson-26/ and http://www.howtostudykorean.com/unit-2-lower-intermediate-korean-grammar/unit-2-lessons-26-33/lesson-29/

That's a good question! I'm waiting for it to be answered! Thanks for asking it!! :)