i bubuneul dasi seolmyeonghae juseyo.

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.

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

Yes, very often in natural speech, Koreans omit object particles when the meaning is clear.

So both of these can sound natural:

• 이 부분을 다시 설명해 주세요.
• 이 부분 다시 설명해 주세요.

The version with 을 is a little more complete and textbook-like. The version without it is very common in everyday speaking.

다시 means again.

It tells you that the speaker wants the explanation one more time:

• 설명해 주세요 = Please explain it
• 다시 설명해 주세요 = Please explain it again

It usually comes before the verb phrase, as in this sentence.

It comes from the verb 설명하다, which means to explain.

The structure is:

• 설명하다 → 설명해
• 주세요 = please give / please do for me

Together, 설명해 주세요 means please explain.

More literally, -아/어 주세요 is a common pattern for making polite requests:

• 도와주세요 = Please help me
• 기다려 주세요 = Please wait
• 설명해 주세요 = Please explain

Both can be used, but they feel different.

• 설명해 주세요 = Please explain
  • sounds like a request
  • soft and common in everyday polite speech
• 설명하세요 = Explain
  • still polite in form, but can sound more direct or instructional depending on context

If you are asking a teacher, coworker, or customer-service person to explain something, 설명해 주세요 is usually the more natural choice.

It is polite and appropriate for many everyday situations.

The ending 주세요 makes it a polite request, so this works well when speaking to:

• a teacher
• a classmate you want to speak politely to
• a coworker
• staff or customer support

It is not the most formal possible version, but it is very normal and respectful.

A more formal version could be:

• 이 부분을 다시 설명해 주시겠어요?
• 이 부분을 다시 설명해 주십시오.

But 이 부분을 다시 설명해 주세요 is already very useful and natural.

These words all relate to this/that, but from different perspectives:

• 이 = this (near the speaker)
• 그 = that (near the listener or already mentioned)
• 저 = that over there (far from both)

So:

• 이 부분 = this part
• 그 부분 = that part
• 저 부분 = that part over there

In a classroom or while looking at a document together, 이 부분 is very natural if you are pointing to the specific part you mean.

Yes, the meaning is the same.

You will see both:

• 설명해 주세요
• 설명해주세요

In everyday writing, both are common. The spaced version can make the grammar easier to see for learners, because it shows 해 + 주세요 more clearly.

So for study purposes, 설명해 주세요 is often easier to understand, but 설명해주세요 is also very common in real life.

Korean usually follows Subject-Object-Verb order, and the verb comes at the end.

In this sentence:

• 이 부분을 = this part
• 다시 = again
• 설명해 주세요 = please explain

So the order is:

this part + again + please explain

That is why the verb phrase comes last.

Yes, but the tone changes.

• 설명해 주세요 = polite, standard request
• 설명해 줄래요? = more casual / softer in a conversational way

줄래요? is often used with people you are closer to, or in less formal situations. It can sound friendly, but it may be too casual for a teacher, boss, or stranger.

So if you want a safe, polite option, 이 부분을 다시 설명해 주세요 is the better choice.