[Korean Grammar] -아서 / -어서 / -여서

-아서 / -어서 / -여서

If you’ve learned basic Korean verbs, you’re ready for one of the most common real-life grammar patterns:

-아서 / -어서 / -여서
👉Used to give a reason (like “because” in English)

You’ll hear this grammar every day in conversations!

1️⃣ What Does -아서/어서/여서 Mean?

It connects two clauses and means:

“because…”
“so…” (showing the reason for the next action or situation)

Structure

Verb/Adjective stem + 아서 / 어서 / 여서

Stem Vowel	Ending	Example
ㅏ or ㅗ	-아서	가다 → 가서
other vowels	-어서	먹다 → 먹어서
하다	-여서 → 해서	공부하다 → 공부해서

 

2️⃣ Basic Examples

👉  늦어서 죄송해요.  I’m sorry because I’m late.

👉 비가 와서 집에 있었어요.  I stayed home because it rained.

 

👉 피곤해서 일찍 잤어요.  I went to bed early because I was tired.

👉 비싸서 안 샀어요.  I didn’t buy it because it was expensive.
👉 날씨가 좋아서 기분이 좋아요.  I feel good because the weather is nice.

 

3️⃣ VERY Important Rule ⚠️

❌ You CANNOT use this with commands or suggestions

-아서/어서 does NOT work well with:

• commands (하세요, 가세요)
• suggestions (같이 가요, 먹을까요?)

🚫 Wrong:
배고파서 밥을 드세요.❌ (Eat because you are hungry)

✅ Instead, use -(으)니까
배고프니까 밥을 드세요. 👉 You’re hungry, so please eat.

 

Quick Tip:
-아서/어서 = natural reason/result
-(으)니까 = reason used for advice, commands, suggestions

 

4️⃣  Common Daily Expressions

These are used ALL the time:

Korean	Meaning
미안해서…	Because I’m sorry…
고마워서…	Because I’m thankful…
아파서…	Because I’m sick…
바빠서…	Because I’m busy…

👉 바빠서 전화를 못 받았어요.
I couldn’t answer the phone because I was busy.

 

5️⃣  Difference from “because” in English

In English, we often start with Because + sentence.

But in Korean, -아서/어서 is attached directly to the verb:

❌ Because I was tired, I slept early.
✅ 피곤해서 일찍 잤어요.

It feels smoother and more connected than English “because.”

 

6️⃣Mini Practice

Try making your own sentences:

1. I didn’t go because I was sick.
   👉 아파서 __________
2. I was happy because I met my friend.
   👉 친구를 만나서 __________
3. It was cold, so I wore a coat.
   👉 추워서 __________

✅ Final Summary

-아서 / -어서 / -여서 = “because / so”

✔ Used for natural reasons
✔ Very common in daily conversation
❌ Not used with commands or suggestions