-는데

V/Adj/이다,아니다 + 는/ㄴ/은데 1. This indicates the contras. (but) This meaning of -는데 can replace -지만.

이 티셔츠는 예쁘지만 비싸요.

= 이 티셔츠는 예쁜데 비싸요.

This T-shirt is pretty but expensive.

이 열쇠는 작은데 무거워요.

key is small but heavy

언니는 매운 음식을 잘 먹는데 저는 잘 못 먹어요.

My older sister can eat spicy food well but I can't eat it well.

V/Adj/이다,아니다 + 는/ㄴ/은데 2. This indicates background information for the following sentence. This concept doesn’t exist in English, which is why many students find it difficult to use naturally. In Korean, however, it is used very frequently. Rather than carrying a fixed meaning, it simply provides context for what follows, so its translation may vary. (and, but, so)

어제 치마를 샀는데 마음에 들어요.

I bought a skirt yesterday and I like it.

어제 치마를 샀는데 마음에 안 들어요.

I bought a skirt yesterday but I don't like it.

죄송한데… 길 좀 물어 볼게요.

Excuse me, let me ask some direction.

• Verb, 있다/없다, -었-/-겠-

Root+는데

ex. 가는데, 먹는데, 듣는데, 만들다→만드는데, 있는데, 없는데(재미있는데, 맛없는데) 갔는데, 가겠는데, 예뻤는데, 예쁘겠는데

있다 and 없다 take '-는데'. Even though 재미있다(fun), 재미없다(not fun), 맛있다(delicious), and 맛없다(not tasty) are adjectives, they still use -는데.

• Adjective, 이다/아니다

받침 X, ㄹ받침	ㄴ데	ex. 큰데, 비싼데, 멀다→먼데, N+인데/아닌데
받침 O	은데	ex. 작은데, 좋은데
	Exception Rule	ex. 더운데, 추운데

• Tense: There are no strict tense restrictions, you can use whatever tense best conveys your intended meaning.