더니 vs 고 나서 vs 자마자: Subtle Differences in Time and Cause Connections

더니 (deo-ni, deoni) · 고 나서 (gona-seo, gonaseo) · 자마자 (ja-ma-ja, jamaja)

더니 (deoni) contrasts past experience with current situation, 고 나서 (go naseo) shows sequential actions, and 자마자 (jamaja) indicates immediate succession.

Comparison of Korean conjunctions 더니, 고 나서, 자마자 for time and cause

Word-by-word breakdown

One lane per word — no nested boxes, just the gist.

더니(deo-ni, deoni)

A connective ending used to contrast past experience or state with the current situation or result

When to use

Past vs present contrast, Speaker's observation, Result emphasis

The nuance

Used after stating a past fact or experience, then connecting it to a resulting or current situation, usually based on the speaker's observation or experience.

고 나서(gona-seo, gonaseo)

A connective ending used to indicate that one action finishes before the next begins

When to use

Clear action sequence, Next action after completion, Planned order

The nuance

Used when the preceding action is completed before the next action or situation follows, emphasizing clear sequence of actions.

자마자(ja-ma-ja, jamaja)

A connective ending used when the next action starts immediately after the preceding one ends

When to use

Immediate succession, No time gap, Rapid consecutive actions

The nuance

Used when the next action starts almost simultaneously right after the preceding action ends, indicating minimal time gap.

Real-world examples

  • 비가 오더니 길이 미끄러워졌어요.

    bi-ga o-deo-ni gil-i mi-kkeu-reo-wo-jyeoss-eo-yo., bi ga o deo ni gil i mi kkeu reo wo jyeoss eo yo.

    '더니' is appropriate because it contrasts past rain with current slippery road as a result.

  • 밥을 먹고 나서 이를 닦았어요.

    bap-eul meok-go na-seo i-reul dakk-ass-eo-yo., bap eul meok go na seo i reul dakk ass eo yo.

    '고 나서' is correct because one action finishes before the next begins.

  • 수업이 끝나자마자 친구를 만났어요.

    su-eop-i kkeut-na-ja-ma-ja chin-gu-reul man-nass-eo-yo., su eop i kkeut na ja ma ja chin gu reul man nass eo yo.

    '자마자' fits because the next action starts immediately after the previous one.

  • 어제 영화를 보자마자 잠들었어요.

    eo-je yeong-hwa-reul bo-ja-ma-ja jam-deul-eoss-eo-yo., eo je yeong hwa reul bo ja ma ja jam deul eoss eo yo.

    '자마자' emphasizes immediate succession of falling asleep after watching.

  • 비가 오고 나서 길이 미끄러워졌어요.

    bi-ga o-go na-seo gil-i mi-kkeu-reo-wo-jyeoss-eo-yo., bi ga o go na seo gil i mi kkeu reo wo jyeoss eo yo.

    '고 나서' is for sequential actions; '더니' better connects cause and result here.

  • 밥을 먹더니 이를 닦았어요.

    bap-eul meok-deo-ni i-reul dakk-ass-eo-yo., bap eul meok deo ni i reul dakk ass eo yo.

    '더니' contrasts past and present; '고 나서' suits simple sequential actions.

  • 수업이 끝나고 나서 바로 집에 갔어요.

    su-eop-i kkeut-na-go na-seo ba-ro jip-e gass-eo-yo., su eop i kkeut na go na seo ba ro jip e gass eo yo.

    '고 나서' fits because the next action follows after completion.

  • 수업이 끝나더니 바로 집에 갔어요.

    su-eop-i kkeut-na-deo-ni ba-ro jip-e gass-eo-yo., su eop i kkeut na deo ni ba ro jip e gass eo yo.

    '더니' contrasts past and present; '고 나서' better for clear sequential order.

Quick quiz

  1. Which connective indicates 'immediate succession'?

    다음 중 '즉각적인 동시성'을 나타내는 연결 어미는?(da-eumjung'jeuk-gak-jeok-indong-si-seong'eulna-ta-nae-neunyeon-gyeoleo-mi-neun?, daeumjung'jeukgakjeokindongsiseong'eulnatanaeneunyeongyeoleomineun?)
  2. Which connective is appropriate for contrasting past experience with current situation?

    '과거 경험과 현재 상황의 대조'를 표현할 때 적절한 연결 어미는?('gwa-geogyeong-heom-gwahyeon-jaesang-hwang-uidae-jo'reulpyo-hyeon-halttaejeok-jeol-hanyeon-gyeoleo-mi-neun?, 'gwageogyeongheomgwahyeonjaesanghwanguidaejo'reulpyohyeonhalttaejeokjeolhanyeongyeoleomineun?)
  3. Which connective is used when one action finishes before the next begins?

    '행동이 끝난 후 다음 행동이 이어질 때' 쓰는 연결 어미는?('haeng-dong-ikkeut-nanhuda-eumhaeng-dong-ii-eo-jilttae'sseu-neunyeon-gyeoleo-mi-neun?, 'haengdongikkeutnanhudaeumhaengdongiieojilttae'sseuneunyeongyeoleomineun?)

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