i bubuneul dasi seolmyeonghae juseyo.

Please explain this part again.

Breakdown of i bubuneul dasi seolmyeonghae juseyo.

• ~을: object particle
• 이: this
• 다시: again
• ~주세요: please (polite request/imperative)

Questions & Answers about i bubuneul dasi seolmyeonghae juseyo.

What does 이 부분을 mean exactly?

이 부분을 means this part or this section.

• 이 = this
• 부분 = part, section, or portion
• 을 = the object marker

So 이 부분을 다시 설명해 주세요 is literally something like Please explain this part again.

Why is 을 used after 부분?

을/를 marks the direct object of the verb.

In this sentence, the thing being explained is 이 부분 (this part), so it takes the object marker:

• 부분
  • 을 → 부분을

Because 부분 ends in a consonant, you use 을 rather than 를.

Compare:

• 책을 읽어요 = I read a book
• 문제를 풀어요 = I solve a problem
• 이 부분을 설명해 주세요 = Please explain this part

Can I leave out 을 in conversation?