From www.howtostudykorean.com ~ㄴ/은가(요) gets added to the stem of adjectives. Using this form makes a question a little bit softer than using the forms described previously. The exact difference cannot be translated perfectly, but sort of like how “would it be okay if I go into the park?” sounds slightly softer than “can I go into the park.” You add ~ㄴ/은 to adjective stems just like you would when conjugating it to describe a noun: 예쁘다 + ㄴ/은 = 예쁜 작다 + ㄴ/은 = 작은 And then attach “가(요)” after that construction: 예쁜가(요)? 작은가(요)? It is only conjugated into the present tense and therefore usually only used to ask about some sort of present situation. For example: 그 여자는 예쁜가? = Is that girl pretty? 이것은 너무 작은가요? = Is this too small? 그 학교가 좋은가? = Is that school good? 일이 너무 복잡한가요? = Is this work/task too complicated? ~ㄴ/은가(요) is commonly added to 이다 as well. For example: 그 사람이 선생님인가? = Is that person a teacher? 그 사람이 우리 엄마인가? = Is that person our mom? (Is that our mom?) 아닌가(요)? Is very commonly used at the end of a full sentence to say “no?” when you are asking yourself a question as if you are doubting yourself. For example: 그 여자는 한국에서 가장 예쁜 여자야. 아닌가? = That girl is the most beautiful girl in Korea… no?/isn’t she? 너무 복잡해! 아닌가? = This is too complicated. Isn’t it? Using ~나(요) at the end of a sentence to ask a question has the same function of ~ㄴ/은가(요). That is, it can be used to make a question sound slightly softer than the other ways to ask a question. However, ~나(요) is more often used with verbs and with 있다 and 없다. For example: Notice that the ㄹ irregular needs to be applied in appropriate situations again: 밥이 있나? = Is there rice? 사과도 여기서 파나요? = Do you sell apples here too? 소녀시대 콘서트를 여기서 하나요? = Is the Girl’s Generation concert here? 지하철을 타고 있나요? = Are you on (riding) the subway now? This form can be used in the past tense as well. For example: 교통카드가 있었나요? = Did you have your bus (transportation) card? 그 소식을 들었나요? = Did you hear that/the news?

Your question is not clear enough to know. -나 and -가 have so many meanings. Comment me specific information or examples.