Connecting Sentences in Korean: -고, -아서/어서, and -지만

Beginners often speak in short, separate sentences: "I went to the café. I drank coffee. It was good." That is perfectly understandable, but connecting ideas makes your Korean sound much more fluent. Three connectors will take you a long way: -고, -아서/어서, and -지만.

-고: and

-고 connects two actions or descriptions, like "and." Attach it directly to the verb stem.

• 저는 밥을 먹고 커피를 마셔요.

  [jeoneun babeul meokgo keopireul masyeoyo]

  I have a meal and then drink coffee.

• 이 식당은 싸고 맛있어요.

  [i sikdangeun ssago masisseoyo]

  This restaurant is cheap and delicious.

• 주말에 쉬고 영화를 봤어요.

  [jumare swigo yeonghwareul bwasseoyo]

  On the weekend I rested and watched a movie.

Notice that tense is usually marked only on the final verb. 쉬고 does not need a past-tense form because 봤어요 at the end already makes the whole sentence past.

-아서/어서: so, because, and then

-아서/어서 has two main uses. The first is cause: "because" or "so."

• 배가 고파서 라면을 먹었어요.

  [baega gopaseo ramyeoneul meogeosseoyo]

  I was hungry, so I ate ramyeon.

• 비가 와서 집에 있었어요.

  [biga waseo jibe isseosseoyo]

  It rained, so I stayed home.

• 늦어서 미안해요.

  [neujeoseo mianhaeyo]

  Sorry I'm late.

The second use is sequence, when the first action is closely connected to the second, often happening in the same place or with the same object.

• 친구를 만나서 같이 점심을 먹었어요.

  [chingureul mannaseo gachi jeomsimeul meogeosseoyo]

  I met a friend and had lunch together.

• 시장에 가서 과일을 샀어요.

  [sijange gaseo gwaireul sasseoyo]

  I went to the market and bought fruit.

The difference between -고 and -아서 for sequence is subtle. -아서 suggests the second action depends on the first, such as going somewhere and then doing something there. -고 is a more neutral "and then."

The -아서 tense rule

Unlike some other connectors, -아서/어서 never takes past tense itself. Say 늦어서 미안해요, not a past-tense form before 서. The final verb carries the tense.

Also, -아서/어서 is not used before commands or suggestions. For "because it's raining, let's stay home," Korean uses -(으)니까 instead.

• 비가 오니까 집에 있을까요?

  [biga onikka jibe isseulkkayo]

  Since it's raining, shall we stay home?

-지만: but

-지만 means "but" and attaches to the verb stem. It can take past tense.

• 한국어는 어렵지만 재미있어요.

  [hangugeoneun eoryeopjiman jaemiisseoyo]

  Korean is hard but fun.

• 어제는 추웠지만 오늘은 따뜻해요.

  [eojeneun chuwotjiman oneureun ttatteutaeyo]

  It was cold yesterday, but today it's warm.

• 비싸지만 사고 싶어요.

  [bissajiman sago sipeoyo]

  It's expensive, but I want to buy it.

Putting them together

With these three connectors you can tell simple stories.

• 아침에 일어나서 운동하고 샤워했어요.

  [achime ireonaseo undonghago syawohaesseoyo]

  In the morning I got up, exercised, and showered.

• 피곤했지만 기분이 좋았어요.

  [pigonhaetjiman gibuni joasseoyo]

  I was tired, but I felt good.

Common mistakes

• Adding past tense before -아서: keep the tense on the final verb only.
• Using -아서 before a command or suggestion: switch to -(으)니까.
• Forgetting vowel harmony: 가다 → 가서, 먹다 → 먹어서, 하다 → 해서.

A note on -(으)니까

-(으)니까 also means "because," but it often sounds more like "since" and presents the reason as something the listener should accept. It is natural before suggestions and requests, while -아서/어서 is the neutral choice for simple explanations and apologies.

These connectors are the glue of Korean conversation. Once you start using them, your speech will flow much more naturally, and you will understand longer sentences in dramas and articles more easily.