i keompyuteoneun oraedwaessjiman ajik jal jakdonghaeyo.

This computer is old, but it still works well.

Breakdown of i keompyuteoneun oraedwaessjiman ajik jal jakdonghaeyo.

• ~는: topic particle
• 이: this
• 컴퓨터: computer
• ~지만: but

Questions & Answers about i keompyuteoneun oraedwaessjiman ajik jal jakdonghaeyo.

Why is 는 attached to 컴퓨터 here?

는 is the topic particle. It marks 이 컴퓨터 as the thing the sentence is about: as for this computer...

So the sentence is structured like:

• 이 컴퓨터는 = as for this computer
• 오래됐지만 아직 잘 작동해요 = although it’s old, it still works well

A native English speaker often expects a clear subject every time, but Korean often starts by setting a topic instead. That topic can then carry through the rest of the sentence.

---

Could this sentence use 이 컴퓨터가 instead of 이 컴퓨터는?

Yes, but the nuance changes.

• 이 컴퓨터는 오래됐지만 아직 잘 작동해요.
  = As for this computer, it’s old, but it still works well.

• 이 컴퓨터가 오래됐지만 아직 잘 작동해요.
  is less natural in a neutral situation, and 가 would put more focus on this computer itself as the subject.

In many everyday statements like this, 는 sounds more natural because you are introducing or commenting on a topic.

A simple way to think about it:

• 는 = topic / contrast / general comment
• 가 = subject / focus / identification

---

What is the base form of 오래됐지만?