The grammatical construction – -ㄴ/은/는데 means “but,” “however,” “so,” “and.” But -ㄴ/은/는데 (-n/eun/neunde) can also convey to the listener that a consequent and relevant statement is immediately coming.
When a sentence ends with -ㄴ/은/는데, this means the speaker is indicating a different idea or another possibility, or it can be a signal for feedback. It must be interpreted from context what the speaker is inferring.
This sentence structure is often used for linking sentences together in order to tell a story.
미안해 누나. 이 방이 더운데… (성풍기를 켜줘.)
(mianhae nuna. i bang-I deounde…)
Sorry sister. This room is a little hot… (so please turn on the fan.)
이거는 맛있는데… (너무 싱거워.)
igeo-neun masineunde… (neomu singgeowo)
This is delicious… (but it’s too bland)
이거는 맛있는데… (너는 어떻게 생각 해?)
[igeo-neun masineunde… (neo-neun eotteoke saenggak hae?)]
This is delicious… what do you think?
As seen in the last two examples, it must be inferred from context what the speaker is indicating.
You can attach
(a) -ㄴ데 to a descriptive verb stem ending in a vowel (present tense). This also attaches to the copula.
활발 하다 – (hwalbal hada) – to be lively, to be active, to be full of life
활발 하 – (hwalbal ha) – verb stem
화발 한데… – (hwalbal hande…) – [(He) is full of life…]
(b) -은데 to a descriptive verb stem root ending in a consonant (present tense).
귀찮다 – (gwichanta) – to be annoying
귀찮 – (gwichan) – verb stem
귀찮은데… – (gwichanheunde…) – [(It) is annoying…]
(c) -는데 to a verb stem (action verbs, and all verbs in forms other than the present tense)
쉬다 – (swida) – to rest
쉬 – (swi) – verb stem
쉬는데… – (swineunde…) – [(She) is resting…]
1.이거 무거운데, 들어줘.
(igeo mugeounde, deuleojwo)
This is heavy, so please hold it for me.
2.저는 한국어를 공부하는데, 너무 재미있어요.
((hangukeo-reul gongbuhaneunde, neomu jaemiisseoyo.)
I’m studying Korean, and it’s so fun.
3.나 부탁 하나 있는데…
(na butak hana ineunde…)
I have a favor… (inference: please honor it, or please listen)
The verb 이다 becomes '인데'
Verb inflections are inflected before the addition of -ㄴ/은/는데.
(e.g. past tense inflection: 봤는데)
If this structure is used as sentence ending, the politeness marker –요, can be added to the end (-ㄴ/은/는데요).