Hi! I just tried to look for a basic/intermediate lesson that covers verb ending ㄴ/는데, but I couldn't find any. You can't find it in the grammar bank either.
Could you add it or tell me which lesson notes should I look at?
It looks like that this grammatical structure is included to grammar bank after all. Anyway, it doesn't seem to be completed, though.
1. to give common background information to be shared between a speaker and a listener (example: 비가 오는데 우산이 없어요. --> English "translation": but, even if, etc.)
2. to contrast to clauses (example: 읏이 예쁜데, 너무 비싸요. --> English "translation": however, despite, etc.)
3. to justify a request or proposal (example: 시간이 없는데 택시를 타세요. --> English "translation": so, therefore, etc.)
The sentence ending ㄴ/은데요 & 는데요 is extended usage of clausal connective. [...] the speaker presents background information and lets the listener figure out what to do. Thus, it may be used as an expression of politeness. [...] is also used to deal with delicate situations such as disagreement, denial, and rejection. [...] allows speaker to avoid explicitly stating their intentions.
１．는데
接続語尾는데は、ゆるい因果関係で前係を結びつけ、文脈によって以下のような様々な意味になる。
①前置き：～なんだが、～しているところに
②逆接：～けれども（=지만）、～のに（=는데도）
③理由：～だし（=니까）、なので
２．는데요
①婉曲、余韻：～ですけど
②不満：～のに
③感嘆：～ですね、～ですよ