Is ~는데 a contraction of 그런데?
I watched a video where a native Korean speaker who teach Korean on a website, explained how to say the sentence "I understood, and/but still I'm thinking" in Korean.
He firstly wrote "알아들었어요. 그런데 생각하고 있어요", and immediately after that, he told that sentence (wich is made by 2 clauses), could be convined or shortened like this:
"알아들었는데 생각하고 있어요"

So, my question is, is ~는데 a shortened form of the word 그런데? Are these 2 used for the same kind of sentences and mean the same?
Thank you so much for your answers! :)

Question

Is ~는데 a contraction of 그런데?
I watched a video where a native Korean speaker who teach Korean on a website, explained how to say the sentence "I understood, and/but still I'm thinking" in Korean.
He firstly wrote "알아들었어요. 그런데 생각하고 있어요", and immediately after that, he told that sentence (wich is made by 2 clauses), could be convined or shortened like this:
"알아들었는데 생각하고 있어요"

So, my question is, is ~는데 a shortened form of the word 그런데? Are these 2 used for the same kind of sentences and mean the same?
Thank you so much for your answers! :)

Answer

It's not exactly the shortened form, but I think the verb " 그러다 " is joined by the " ㄴ데 ". so it follows the rule, explained on the website below:

http://www.talktomeinkorean.com/lessons/level-3-lesson-21/

I hope it helps

Answer

they are not the same.  는데 is usually reserved for occasions where there's a kind of hesitation (often time there is a message but not verbally expressed yet) so it is sort of like "..." as if there were more to follow.  Sometimes it is kind of giving a suspense effect.

그런데 is similar to "but, however".  in other words they serve different purposes.

by the way, one thing to watch out for.  you may come across 는 데 with a space in between.  This is something totally different from 는데 without the intervening space.  with a space in between that 데 is a noun and it means "place, a spot".  Make careful distinction because they are two different structures and grammatically unrelated.