V+아/어서

Overview

V+아/어서 is a versatile connective ending used to link two clauses. It primarily serves two functions: expressing a reason or cause for the following action/state, or indicating a sequence of events where the first action naturally leads to or precedes the second. It's one of the most fundamental and frequently used connective endings in Korean.

---

Usage

1. Expressing Reason or Cause This is the most common use of V+아/어서. The first clause provides the reason or cause for the action or state described in the second clause. It implies a natural or objective cause-and-effect relationship.

   • Cannot be used with commands (-(으)세요) or propositions (-(으)ㅂ시다) in the second clause when expressing a reason. For such cases, -(으)니까 is typically used.
   • Example: 비가 와서 집에 있었어요. (Because it rained, I stayed home.)
   • Example: 머리가 아파서 약을 먹었어요. (Because my head hurt, I took medicine.)

2. Expressing a Sequence of Events V+아/어서 can also indicate that the action in the first clause occurs before the action in the second clause. This sequence often implies that the first action is a necessary prerequisite or a natural step leading to the second action. The subject of both clauses is usually the same.

   • Unlike the 'reason' usage, when expressing a sequence, it can be followed by commands or propositions.
   • Example: 아침을 먹어서 학교에 갔어요. (I ate breakfast and then went to school.)
   • Example: 집에 가서 쉬세요. (Go home and then rest.)

---

Conjugation Rules

V+아/어서 attaches to the stem of verbs and adjectives. The form depends on the final vowel of the stem:

• Stems ending in ㅏ or ㅗ: Add -아서.

  • 가다 (to go) -> 가 + 아서 -> 가서
  • 오다 (to come) -> 오 + 아서 -> 와서 (vowel contraction)
  • 좋다 (to be good) -> 좋 + 아서 -> 좋아서

• Stems ending in any other vowel (excluding ㅏ/ㅗ) or a consonant: Add -어서.

  • 먹다 (to eat) -> 먹 + 어서 -> 먹어서
  • 읽다 (to read) -> 읽 + 어서 -> 읽어서
  • 배우다 (to learn) -> 배우 + 어서 -> 배워서 (vowel contraction)
  • 만들다 (to make) -> 만들 + 어서 -> 만들어서

• Stems ending in 하다: Change to -해서.

  • 공부하다 (to study) -> 공부 + 하여서 -> 공부해서
  • 운동하다 (to exercise) -> 운동 + 하여서 -> 운동해서

• Irregular Verbs:

  • ㅂ irregular: 돕다 (to help) -> 도와서, 춥다 (to be cold) -> 추워서
  • ㄷ irregular: 듣다 (to listen) -> 들어서, 걷다 (to walk) -> 걸어서
  • 르 irregular: 모르다 (to not know) -> 몰라서, 부르다 (to call/sing) -> 불러서

---

Knowledge Plus

• No Tense Marker in the First Clause: When using V+아/어서, the tense of the entire sentence is determined by the final verb in the second clause. The first clause does not take a past tense marker (았/었).

  • 어제 피곤해서 일찍 잤어요. (O) - Yesterday, because I was tired, I slept early.
  • 어제 피곤했어서 일찍 잤어요. (X)

• Distinction from -(으)니까:

  • V+아/어서 expresses an objective, generally accepted reason or a natural consequence. It cannot be used with commands or propositions when stating a reason.
  • -(으)니까 expresses a subjective reason or a reason discovered by the speaker. It can be used with commands or propositions.
  • Example (Reason + Command):
    • 피곤하니까 쉬세요. (O) - Because you're tired, please rest.
    • 피곤해서 쉬세요. (X)
  • Example (Sequence + Command):
    • 집에 가서 쉬세요. (O) - Go home and then rest.

• Cannot be used with negative commands (지 마세요) or negative propositions (지 맙시다) when expressing a reason.

  • 비가 와서 가지 마세요. (X)
  • 비가 오니까 가지 마세요. (O)