TOPIK I: Connective - '-더니' (Observed Change)

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TOPIK I Prep
💡
TL;DR
  • -더니 connects an observed past situation to a later change, result, or contrast.
  • In TOPIK questions, look for clues like 아까, 전에는, 처음에는, 요즘, 이제, 갑자기.
  • Do not use -더니 for a simple personal plan; it usually sounds like the speaker observed something.
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🎧 Helper Note
Read each Korean example aloud twice. First, stress the before situation before -더니; second, stress the after/result part after -더니.

🔑 The Big Picture

-더니 is a connective ending used when the speaker remembers or observed something in the past and connects it to what happened later.
It often means:
  • “I noticed that … and then …”
  • “It was …, but now …”
  • “Because/after that observable situation, …”
For TOPIK I-style reading and grammar practice, the most important skill is recognizing the relationship:
Pattern
Meaning
Example
A/V + 더니
Observed past → later change/result
아까는 비가 오더니 지금은 맑아요.
N + 이더니
It was N → later change/result
어제는 학생이더니 오늘은 선생님처럼 설명해요.

🧩 Core Concepts / Patterns

1. Form

For verbs and adjectives, attach -더니 directly to the stem.
  • 오다 → 오더니
  • 춥다 → 춥더니
  • 많다 → 많더니
  • 공부하다 → 공부하더니
For nouns, use 이다 + 더니.
  • 학생이다 → 학생이더니
  • 방학이다 → 방학이더니
  • 친구이다 → 친구이더니 / 친구더니

2. Observed change

Use -더니 when the first clause is something the speaker saw, heard, noticed, or experienced as an observation.
  • 아침에는 날씨가 춥더니 오후에는 따뜻해졌어요.
  • 아이가 계속 울더니 잠이 들었어요.
  • 친구가 열심히 공부하더니 시험을 잘 봤어요.

3. Contrast: before vs now

-더니 often contrasts an earlier state with a later state.
  • 전에는 김치를 못 먹더니 이제는 잘 먹어요.
  • 어제는 피곤하더니 오늘은 괜찮아 보여요.
  • 처음에는 어렵더니 계속 하니까 쉬워졌어요.

4. Cause or result through observation

Sometimes -더니 shows that the second event naturally followed from the first.
  • 밤새 눈이 오더니 길이 미끄러워요.
  • 많이 연습하더니 발음이 좋아졌어요.
  • 며칠 동안 아프더니 병원에 갔어요.

✅ Exam Strategy

Step 1: Find time contrast words

TOPIK-style questions often include words that show a time shift.
  • Past/earlier: 아까, 어제, 전에는, 처음에는, 지난주에는
  • Later/now: 지금은, 오늘은, 이제는, 갑자기, 결국
If you see “earlier situation → now different result,” -더니 is often a strong candidate.

Step 2: Check whether the first clause is observable

Good -더니 clauses often describe something visible or noticeable:
  • 날씨가 춥다
  • 사람이 많다
  • 친구가 공부하다
  • 아이가 울다
  • 가게가 조용하다

Step 3: Ask: “Did something change?”

If the sentence means “It was X, but then became Y,” use -더니.
  • 사람이 별로 없더니 금방 많아졌어요.
  • 처음에는 조용하더니 갑자기 시끄러워졌어요.

⚠️ Pitfalls

Pitfall 1: Confusing -더니 with -(으)니까

-(으)니까 gives a direct reason: “because/since.”
  • 비가 오니까 우산을 가져가세요. = Since it is raining, take an umbrella.
  • 비가 오더니 길이 막혀요. = It was raining, and now the roads are jammed.

Pitfall 2: Using it for a simple personal intention

-더니 is not usually for “I will do A and then B.”
Awkward:
  • 저는 집에 가더니 쉬겠어요.
Better:
  • 저는 집에 가서 쉬겠어요.

Pitfall 3: Forgetting the observation feeling

-더니 sounds like the speaker is reporting a remembered observation. It is very common with third-person subjects, weather, places, and visible situations.
Natural:
  • 동생이 많이 먹더니 배가 아프대요.
  • 아까는 사람이 많더니 지금은 조용해요.
📝
Practice Hub — 50 Questions
Complete all 5 sets. Each set has 10 questions. Check the hidden answers only after you try.

Set 1 — Choose the correct -더니 form

Choose the best form for each blank.
  1. 아침에는 비가 많이 (오다) → 지금은 그쳤어요.
  1. 처음에는 한국어가 (어렵다) → 이제는 재미있어요.
  1. 친구가 매일 운동을 (하다) → 건강해졌어요.
  1. 어제는 사람이 별로 (없다) → 오늘은 많아요.
  1. 아이가 계속 (울다) → 잠이 들었어요.
  1. 날씨가 갑자기 (춥다) → 눈이 왔어요.
  1. 동생이 밥을 많이 (먹다) → 배가 아프대요.
  1. 가게가 전에는 (작다) → 지금은 커졌어요.
  1. 민수가 열심히 (공부하다) → 시험을 잘 봤어요.
  1. 이 길이 어제는 (복잡하다) → 오늘은 한산해요.
Answers — Set 1
  1. 오더니 — observed weather change.
  1. 어렵더니 — earlier difficulty changed into interest.
  1. 하더니 — repeated observed action led to result.
  1. 없더니 — contrast between yesterday and today.
  1. 울더니 — crying was followed by sleep.
  1. 춥더니 — cold weather led to snow.
  1. 먹더니 — eating a lot led to stomachache.
  1. 작더니 — past size contrasts with current size.
  1. 공부하더니 — studying led to good result.
  1. 복잡하더니 — past traffic condition contrasts with today.

Set 2 — Choose the best meaning

Choose the best English meaning.
  1. 아까는 조용하더니 지금은 시끄러워요.
A. It is quiet because it is noisy.
B. It was quiet earlier, but now it is noisy.
C. It will be quiet later.
D. It is always noisy.
  1. 친구가 계속 웃더니 갑자기 울었어요.
A. My friend kept laughing and then suddenly cried.
B. My friend cried before laughing.
C. My friend never laughed.
D. My friend laughed because I cried.
  1. 지난주에는 춥더니 이번 주에는 따뜻해요.
A. It is cold every week.
B. It was cold last week, but it is warm this week.
C. It will be warm next week.
D. It is warm, so it is cold.
  1. 학생들이 많이 연습하더니 발표를 잘했어요.
A. The students practiced a lot and then gave a good presentation.
B. The students did not practice.
C. The presentation was bad because they practiced.
D. The students will practice tomorrow.
  1. 처음에는 길이 막히더니 조금 후에 괜찮아졌어요.
A. The road was never busy.
B. The road was busy at first, but got better later.
C. The road will be closed.
D. The road is always easy.
  1. 동생이 하루 종일 자더니 밤에 잠을 못 잤어요.
A. My younger sibling slept all day and then could not sleep at night.
B. My younger sibling did not sleep all day.
C. My younger sibling slept well at night because they studied.
D. My younger sibling will sleep tomorrow.
  1. 전에는 매운 음식을 못 먹더니 이제는 잘 먹어요.
A. They could not eat spicy food before, but now they eat it well.
B. They still cannot eat spicy food.
C. They will cook spicy food later.
D. They ate spicy food yesterday only.
  1. 아기가 울더니 엄마가 오자 조용해졌어요.
A. The baby cried, then became quiet when the mother came.
B. The mother cried because the baby was quiet.
C. The baby always sleeps.
D. The baby did not cry.
  1. 커피를 많이 마시더니 잠을 못 잤어요.
A. They drank a lot of coffee and then could not sleep.
B. They slept before drinking coffee.
C. They never drink coffee.
D. They drank coffee because they slept well.
  1. 어제는 문이 닫혀 있더니 오늘은 열려 있어요.
A. The door was closed yesterday, but it is open today.
B. The door is always closed.
C. The door will close tomorrow.
D. The door opened because yesterday disappeared.
Answers — Set 2
  1. B — earlier quiet state contrasts with current noise.
  1. A — observed action changed suddenly.
  1. B — last week vs this week contrast.
  1. A — practice led to a good result.
  1. B — initial condition changed later.
  1. A — sleeping all day caused a later result.
  1. A — past inability contrasts with current ability.
  1. A — crying changed to quietness.
  1. A — coffee caused an observable result.
  1. A — yesterday’s state contrasts with today’s state.

Set 3 — Find and correct the error

Each sentence has one problem. Rewrite it naturally using -더니.
  1. 아까 비가 오니까 지금은 맑아요.
  1. 처음에는 어려워서 이제는 쉬워졌어요.
  1. 친구가 공부해서 시험을 잘 봤더니.
  1. 어제는 사람이 많고 오늘은 없더니.
  1. 아이가 울어서 잠이 들더니.
  1. 전에는 커피를 안 마시니까 이제는 매일 마셔요.
  1. 날씨가 추워서 눈이 오더니.
  1. 동생이 밥을 많이 먹고 배가 아프더니.
  1. 가게가 작아서 지금은 커졌더니.
  1. 아침에는 조용하니까 오후에는 시끄러워요.
Answers — Set 3
  1. 아까 비가 오더니 지금은 맑아요. — use observed weather change, not direct reason.
  1. 처음에는 어렵더니 이제는 쉬워졌어요. — before/after contrast fits -더니.
  1. 친구가 공부하더니 시험을 잘 봤어요. — sentence must finish after the result clause.
  1. 어제는 사람이 많더니 오늘은 없어요. — put -더니 after the first observed state.
  1. 아이가 울더니 잠이 들었어요. — first action leads to later result.
  1. 전에는 커피를 안 마시더니 이제는 매일 마셔요. — past habit contrasts with current habit.
  1. 날씨가 춥더니 눈이 왔어요. — first clause is the observed condition.
  1. 동생이 밥을 많이 먹더니 배가 아프대요. — eating a lot led to stomachache.
  1. 가게가 작더니 지금은 커졌어요. — past state contrasts with present result.
  1. 아침에는 조용하더니 오후에는 시끄러워요. — time contrast fits -더니.

Set 4 — Complete the sentence

Choose the best ending.
  1. 아까는 교실에 학생이 많더니 (    ).
A. 지금은 조용해요
B. 학생이 많아서 많아요
C. 내일 공부할 거예요
D. 책을 읽으세요
  1. 민수가 매일 운동하더니 (    ).
A. 건강해졌어요
B. 어제 책이에요
C. 날씨가 좋아요
D. 운동하지 마세요
  1. 처음에는 이 문법이 어렵더니 (    ).
A. 이제는 조금 이해돼요
B. 어제는 시장이에요
C. 저는 밥을 먹어요
D. 비가 와요
  1. 아이가 계속 울더니 (    ).
A. 곧 잠이 들었어요
B. 오늘은 금요일이에요
C. 책상이 커요
D. 한국어를 배워요
  1. 전에는 지하철이 복잡하더니 (    ).
A. 요즘은 조금 한산해요
B. 내 이름은 수미예요
C. 물을 마셔요
D. 사과가 맛있어요
  1. 밤새 눈이 오더니 (    ).
A. 길이 미끄러워요
B. 저는 영화를 봐요
C. 학생입니다
D. 책을 샀어요
  1. 친구가 한국 노래를 많이 듣더니 (    ).
A. 발음이 좋아졌어요
B. 의자가 작아요
C. 문이 닫혀 있어요
D. 밥을 먹지 마세요
  1. 어제는 가게가 닫혀 있더니 (    ).
A. 오늘은 열려 있어요
B. 그래서 연필이에요
C. 내일은 비싸요
D. 저는 선생님이에요
  1. 동생이 과자를 많이 먹더니 (    ).
A. 저녁을 못 먹었어요
B. 학교가 멀어요
C. 어제는 춥겠어요
D. 노래를 좋아하세요
  1. 처음에는 사람들이 줄을 서 있더니 (    ).
A. 조금 후에 모두 들어갔어요
B. 저는 집에 갈 거예요
C. 창문이 작습니다
D. 물건이 비싸요
Answers — Set 4
  1. A — contrast from crowded to quiet.
  1. A — exercise led to improved health.
  1. A — difficult at first, now understandable.
  1. A — crying followed by sleep.
  1. A — crowded before, less crowded now.
  1. A — snow caused slippery roads.
  1. A — listening practice led to better pronunciation.
  1. A — yesterday closed, today open.
  1. A — eating snacks affected dinner.
  1. A — people lined up, then entered.

Set 5 — TOPIK-style short reading questions

Read each sentence and choose the best answer.
  1. 아침에는 날씨가 흐리더니 오후에는 해가 났어요. What changed?
A. The weather became sunny.
B. It became more cloudy.
C. It snowed all day.
D. The morning was sunny.
  1. 지수가 매일 한국어를 듣더니 듣기 점수가 올랐어요. Why did the score improve?
A. Because Jisu listened to Korean every day.
B. Because Jisu stopped studying.
C. Because the test was cancelled.
D. Because the score went down.
  1. 어제는 식당에 사람이 많더니 오늘은 자리가 많아요. Which is true?
A. The restaurant is less crowded today.
B. The restaurant is closed today.
C. There were many seats yesterday.
D. There are no seats today.
  1. 처음에는 이 단어를 모르더니 지금은 잘 써요. What does this mean?
A. They did not know the word at first, but now use it well.
B. They still do not know the word.
C. They used the word well before but not now.
D. They will learn the word tomorrow.
  1. 아이가 밖에서 오래 놀더니 피곤해 보여요. What is the result?
A. The child looks tired.
B. The child is studying.
C. The child went outside because of homework.
D. The child looks hungry only.
  1. 전에는 버스를 타더니 요즘은 걸어서 학교에 가요. What changed?
A. The person used to take the bus but now walks.
B. The person used to walk but now takes the bus.
C. The person never goes to school.
D. The bus is always late.
  1. 민호가 발표를 많이 연습하더니 목소리가 자연스러워졌어요. What improved?
A. Minho’s voice became more natural.
B. Minho’s room became bigger.
C. Minho stopped presenting.
D. Minho’s writing disappeared.
  1. 밤에 바람이 많이 불더니 나무가 쓰러졌어요. What happened after the wind?
A. A tree fell down.
B. The wind stopped before night.
C. The tree was planted.
D. It became very hot.
  1. 지난달에는 돈을 많이 쓰더니 이번 달에는 아껴 쓰고 있어요. Which is true?
A. They spent a lot last month but are saving this month.
B. They saved last month but spend a lot now.
C. They never use money.
D. They will buy a house tomorrow.
  1. 아까는 목소리가 작더니 지금은 잘 들려요. What changed?
A. The voice was quiet earlier, but now can be heard well.
B. The voice is still too quiet.
C. The voice disappeared.
D. The speaker stopped talking yesterday.
Answers — Set 5
  1. A — 흐리다 changed to 해가 나다.
  1. A — daily listening practice led to a higher listening score.
  1. A — yesterday was crowded, today has many seats.
  1. A — lack of knowledge changed into good use.
  1. A — playing outside for a long time led to tiredness.
  1. A — transportation habit changed from bus to walking.
  1. A — repeated presentation practice improved voice/natural delivery.
  1. A — strong wind was followed by a fallen tree.
  1. A — spending habit changed from spending much to saving.
  1. A — earlier quiet voice changed to a clearly audible voice.

Quick Review

Use -더니 when you want to show:
  • Observed past → later result: 많이 연습하더니 잘했어요.
  • Before → now contrast: 전에는 어렵더니 이제는 쉬워요.
  • Noticeable cause → result: 눈이 오더니 길이 미끄러워요.
Before choosing -더니, ask: “Did the speaker observe something first, and did the situation change after that?”