'-(으)ㄴ가요?' and '-나요?' is used when asking someone more politely and cautiously than ‘-요?’
Usage of '-(으)ㄴ가요?' and '-나요?'
With Adjectives and '-(으)ㄴ가요?'
Usage: When used with adjectives, '-(으)ㄴ가요?' is employed. This form is used to ask questions in the descriptive form of the adjective. It is used to politely or gently ask someone a question.
Example:
이 집이 작은가요? (Is this house small?)
요즘 바쁜가요? (Are you busy these days?)
With Adjectives and '-나요?'
Usage: It is also possible to use '-나요?' with adjectives. This form is more casual and natural, and the adjective's form is used directly in the question.
Example:
이 집이 작나요? (Is this house small?)
그 영화가 재미있나요? (Is that movie interesting?)
Combination with Adjectives:
Adjectives Ending in a Consonant:
Usage: When the stem of the adjective ends in a consonant, '-나요?' is used for questions, and the stem remains unchanged.
Example:
이 집이 작나요? (Is this house small?)
날씨가 덥나요? (Is the weather hot?)
Adjectives Ending without a Consonant:
Usage: When the stem of the adjective does not end with a consonant, '-(으)ㄴ가요?' is more commonly used.
Example:
그 가수가 예쁜가요? (Is the singer pretty?)
그 집이 큰가요? (Is the house big?)
With Verbs and '-나요?'
Usage: '-나요?' is used with verbs to form questions. It is also a common way to ask about actions or states politely or gently
Example:
지금 회사에서 일하나요? (Do you work at the company now?)
어제 쇼핑몰에서 옷을 샀나요? (Did you buy the clothes at the shopping mall yesterday?)
Summary
'-(으)ㄴ가요?' is mainly used with the descriptive form of adjectives.
'-나요?' can be used with both adjectives and verbs.
These rules help guide the natural combination of adjectives with question forms in Korean.