-는데 is used for linking or ending 있다, 없다, 계시다 etc in the sentence by following '-으시-’, ‘-었-’, ‘-겠-'. 1.Used for connecting the previous clause to explain, ask, suggest, with related clause in situation. 보고있다(verb)+-는데=보고 있는데 내가 텔레비전을 보고 있는데 전화벨이 울렸다. (While I was watching TV, the phone rang.) 2. Used for ending a sentence to describe something with an exclamation 달리고 있다(verb)+-는데=달리는데 잘 달리는데. (Wow) (the someone) runs very fast. 올랐다(verb)+-는데=올랐는데 성적이 많이 올랐는데? (Wow) Your've got good grades (comparing to ones before) -은데 is similar as -는데. The difference between -는데 and -은데 is -는데 is used for linking a verb in a first sentence with a second sentence to make one sentence, whereas -은데 is used for linking an adjective. 1.많다(adjective, many)+-은데=많은데 볼 것은 많은데 시간이 모자란다. (We) don't have much time, whereas we have a lot to see. Although (we) have a lot to see, there is no enough time. 2 좋다(adjective,good)+-은데=좋은데 기분 좋은데. (I feel good/ I feel nice, or it can be 'I feel better than before', depending on context or situation) 작다(adjective,small)+-은데=작은데 집이 좀 작은데?(The house is rather small (comparing to one that I thought)? If there's perfect one-to-one correspondance between two languages it faciliate to learn them more efficiently. Japanese and Korean shares many those one-to-one correspondance words and structures. However, English doesn't. If I should translate the sentences -은데, -는데 is used in sentences into English, perhaps I have to translated the linking part in some sentences by using connetives, depending on contexts. Because, virtually, there's no one-to-one correspondance Korean and English in -은데, -는데. 휴...It was really tricky question. I hope it helped you some.

In colloquial Korean, we use them a lot for some reasons: 1. to sublty express gratitude or apology If a friend I don't like says "너 돈 좀 있어?", I might say "없어". I'm being blunt here. If my favorite friend says the same, I might say "없는데". It doesn't make a lot of sense if you just translate it as "but I have no money". 없는데 is implying "You want me to lend you some money and so you're asking if I have some extra money, I wish I had some money but I have no money now, I'm sorry". Another example. If my friend cleaned our house by herself and I get home noticing it, we'll probably have a conversation that goes: Me: Hey, did you clean our house all by yourself? Friend: Yeah. It hasn't been cleaner than this, has it? (I notice it took a lot of cleaning and start feeling sorry) Me: It's so clean that my eyes are being dazzled. 그럴 필요까진 없었는데. (You didn't need to do it all by yourself. Thanks heaps) 2. to talk in a manner that's expecting a reply/reaction from the listener Person A : Let's hang out with Joe. Call him. Person B : ...전화 안 받는데? ...but he's not answering it. (What do/should we do about it?) 3. to mean... "and" (sorry, I don't know how else I could explain it) Say I accidentally hit my thumb with a hammer and my friend is laughing her ass off. I might say angrily"난 아파죽겠는데 넌 이게 웃기냐? It's so painful that it kills me and is this funny to you?" Say your friend just made a lame joke about something. It's not a kind comment, but you could say "근데?" meaning "And? (Is that all?)" 는데 with an action verb (먹다 - 먹는데 / 자다 - 자는데 / 공부하다 - 공부하는데) -은데 with an irregular descriptive verb (작다 - 작은데 / 좁다 - 좁은데) ㄴ데 with a regular descriptive verb (예쁘다 - 예쁜데 / 아프다 - 아픈데) Hope that helps!