sueobi kkeutnago naseo chinguwa gati sukjereul haeyo.

After class ends, I do homework together with a friend.

Breakdown of sueobi kkeutnago naseo chinguwa gati sukjereul haeyo.

• ~이: subject particle
• 친구: friend
• ~를: object particle
• ~와: comitative particle
• 수업: class
• 숙제: homework
• 끝나다: to end
• ~고 나서: after
• 같이: together
• ~요: polite ending
• 하다: to do (to make)

Questions & Answers about sueobi kkeutnago naseo chinguwa gati sukjereul haeyo.

Why is it 수업이 (with 이/가) and not 수업은/는?

이/가 marks the subject in a neutral “what happens” way: 수업이 끝나고 나서 = “after class ends.”
You could use 수업은 if you were contrasting class with something else or setting a topic (e.g., “As for class, after it ends…”), but the most natural phrasing here is 수업이 끝나고 나서.

What does 끝나고 나서 mean, and how is it built?

It’s 끝나다 (to end) + -고 (and/then) + 나서 (“after doing…, then…”).
So 끝나고 나서 literally means “(it) ends, and after that…,” i.e. “after it ends.”
It’s a very common sequencing pattern: V-고 나서 … = “After doing V, (then) …”.

Is 끝나다 transitive or intransitive here? Why not 끝내고?

끝나다 is intransitive (“to end” by itself), so 수업이 끝나다 = “class ends.”
끝내다 is transitive (“to end something”), so 수업을 끝내다 = “(someone) ends class.”
If you said 수업을 끝내고 나서, it would imply someone actively ended class (often the teacher or you), which changes the nuance.

What’s the difference between -고 나서 and -고서 or -ㄴ/은 후에?

All can mean “after,” but with slightly different feel:

• V-고 나서: very common, spoken, often implies sequence + “then (next).”
• V-고서: similar meaning, a bit shorter/more written or stylistic.
• V-(으)ㄴ 후에 / 후: more neutral/“afterward,” often slightly more formal.
  Example: 수업이 끝난 후에 is also natural and means essentially the same thing.

Why does it use 친구와? What’s the difference between 와/과 and 하고?

와/과 means “with” (or “and” in lists).
Rule: after a vowel → 와, after a consonant → 과. So 친구(…u) ends in a vowel sound → 친구와.
하고 is also very common in speech and can replace it: 친구하고 같이 = “together with a friend.” The meaning is basically the same, with 하고 sounding a bit more casual/conversational.

Does 같이 mean “together” or “same”? Which one is it here?

같이 can mean both:

• “together” (doing something with someone)
• “the same” (same way/thing)
  Here it’s clearly “together,” because it’s paired with 친구와: 친구와 같이 = “together with a friend.”

Is 친구와 같이 redundant? Could I just say 친구와 숙제를 해요?

It’s not wrong without 같이, but the nuance changes:

• 친구와 숙제를 해요 can sound like “I do homework with my friend” (still fine), but sometimes can feel slightly less explicit about “together.”
• 친구와 같이 숙제를 해요 strongly emphasizes “we do it together.”
  So 같이 adds clarity/emphasis.

Why is it 숙제를 해요 instead of a single verb like “to homework”?

Korean commonly uses a noun + 하다 (“do”) for many actions:

• 숙제하다 = “to do homework”
  In the sentence it’s split as 숙제 + 를 + 해요:
• 숙제 (homework) + 를 (object marker) + 해요 (do, polite).
  You can also say 숙제해요 (more compact, very common).

What does -를 do in 숙제를? When would it be -을?

-를/을 marks the direct object of the verb.
Rule: noun ends in vowel → 를, ends in consonant → 을.
숙제 ends in a vowel sound → 숙제를.
Example with consonant: 밥을 먹어요 (eat rice/meal).

What level of politeness is 해요, and how would I change it?

해요 is the standard polite style (해요체), common in everyday conversation.
Other options:

• Casual: 해 (with close friends)
• More formal/polite: 합니다 → 숙제를 합니다
• Past: 했어요 (did) / 했습니다
• Future/intention: 할 거예요 (will do)

Could I use 수업 끝나고 without 이 and without 나서?

Yes, in casual speech you’ll often hear shortened forms:

• 수업(이) 끝나고 친구랑 숙제해요.
  Dropping 이 is common in conversation, and -고 alone can imply “after/and then.”
  Adding 나서 makes the “after that” sequencing more explicit: 끝나고 나서 feels clearer and slightly more deliberate.