I've read that 이/가 can be used as a particle to mark the complement of the particle 이다, its negative counterpart 아니다, and the verb 되다.

I have seen examples with 아니다 :

나는 아이 아닙니다 – I am not a child.

and 되다

노인 되기 전에 나쁜 짓 해야돼요 - You should have fun (?) before you get old

However, I'm not sure that I've noticed it used with the copula (이다) itself.

Can 이/가 be used as a complement particle with 이다? Can it be used with any constructions other than 이다, 아니다, and 되다?

2 Answers 2


이/가 is used at the end of a noun to express that the noun it accompanies plays the role of the subject of the sentence.

That being said, 이/가 can be used with any verb or the verb-like form of any adjective, and that, naturally, includes 이다.

[Examples with 이다]

  • 내가 이 수업의 선생님이다. (I am the teacher of this class.)
  • 이것이 내가 어제 잃어버린 축구공이다. (This is the soccer ball I lost last night.)

[Examples with other verbs]

  • 의사가 수술을 집도했다. (The doctor performed the surgery.)
  • 내가 갔다. (I went.)

[Examples with verb-like forms of adjectives]

  • 그것보다 이것이 더 맛있다. (This tastes better than that. / This is more delicious than that.)
  • 맥주가 차갑다. (The beer is cold.)

이/가 and 은/는 can be quite confusing for foreigners and some Koreans, but that's a seperate issue.

After reading your comments, I realized that I was confused as well. (Or, only I was.)

According to the dictionary, there are three usages of 이/가, and two of them are about using with nouns.

One is about marking the subject, and I already covered this. The other is about marking the complement.

  • 나는 개구리가 되었다. (I became a frog.)

In this example, the frog is obviously not the subject, but it is the complement. marked the subject 나(I).

You might ask: "If 이/가 can be used to mark both the subject and the complement, can they be used twice in a sentence?" Yes, they can.

  • 올챙이가 개구리가 되었다. (The tadpole became a frog.)

If 이/가 is used twice in a sentence, the first one marks the subject and the last marks the complement.

As far as '이다' and '아니다' are concerned, I am not sure if it is about marking the subject or the complement. Personally I think it's about marking the subject, so I covered in my previous answer. Hope this helps.

  • I am not good with the grammar-related terms, so please take it into account when you read this. Jul 20, 2016 at 8:19
  • I'm not sure that 이/가 has the same function in your examples as in mine - would "나는 이 수업의 선생님이 아니다" or "나는 이 수업의 선생님이 된다" make sense? If so, I think those would be examples of what I mean. Jul 20, 2016 at 8:29
  • Yes, indeed they make perfect sense. (Although using the latter might require some context: For example, 'the teacher who used to teach the class is quitting next week and I will be taking over the class' could be appropriate.) Jul 20, 2016 at 8:36
  • FYI, and I imagine you already know this, making sense and sounding natural are totally different issues in my answers. Some sound natural and make sense, and some only make sense and sound unnatural. Consider this when you read them! Jul 20, 2016 at 8:41
  • Thanks. I think those are examples of using 이/가 to mark the copular complement, and that that's a different function from marking the subject (Which is '나' in both my examples). But I could be confused. Jul 20, 2016 at 8:41

Adding to Cheong's great answer, the particle 이/가, in short, can be used as subject particles for any adjectives or verbs, and must be used as object equivalent if the word means a verb, but sometimes act as an adjective.

For example: 되다, 아니다, 있다, 없다, 그립다(miss).

네가 그 아이가 아니다.

거기서 버스가 있다.

어머니가 그리웠냐?

In the 3 examples above, the noun is treated as objects in English, but 이/가 used instead.

For the verb 이다, 이/가 is never added to the object. (AT LEAST, I have seen none yet).

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.