jinanbeone mannan seonsaengnimeul oneul dasi bwaseo jeongmal bangawosseo.

Because Korean puts modifying clauses before the noun they describe.

So:

지난번에 만난 선생님
= the teacher whom I met last time

Here, 만난 is the noun-modifying form of 만나다 (to meet) in the past, so it describes 선생님.

지난번 means last time, the previous time, or the other day, depending on context.

The particle 에 marks a point in time, so 지난번에 means last time / on the previous occasion.

So:

지난번에 만난
= met last time

을/를 marks the direct object of the verb.

In this sentence, the teacher is the person being seen in 보다 (to see), so 선생님을 is correct.

A very literal breakdown is:

지난번에 만난 선생님을
= the teacher I met last time + object marker

다시 means again.

It shows that the speaker had already seen this teacher before and then saw them one more time today.

So:

오늘 다시 봐서
= because I saw [them] again today
or more naturally,
= to see [them] again today

봐서 is 보다 + -아서/어서, a connective ending.

This ending can link clauses in a few ways, often like:

• because
• so
• sometimes just a natural sequence, like and then

In this sentence, the most natural interpretation is:

오늘 다시 봐서 정말 반가웠어
= I was really glad because I saw [them] again today

In smoother English, you would often say:

It was really nice to see the teacher I met last time again today.

So even though Korean may look like because I saw, the natural English meaning is often it was nice to see.

반갑다 means to be glad, to be pleased, or to be happy to see someone.

The past form 반가웠어 is used because the speaker is talking about the feeling they had in that situation. Korean often uses the past tense for feelings connected to a completed event.

So:

정말 반가웠어
= I was really glad
or more naturally,
= It was really nice

This is a very common learner question.

• 반갑다 describes a person’s feeling directly.
• 반가워하다 is usually used when talking about someone else’s visible reaction or when describing that they seemed glad.

Since the speaker is talking about their own feeling, 반가웠어 is natural.

So:

• 반가웠어 = I was glad / It was nice
• 반가워했어 = He/She showed that they were glad

The subject is omitted because it is understood from context.

Korean often leaves out subjects like I, you, or he/she when they are obvious.

In this sentence, the understood subject is most likely I:

(나는) 지난번에 만난 선생님을 오늘 다시 봐서 정말 반가웠어.
= I was really glad to see the teacher I met last time again today.

반가웠어 is informal, casual, non-polite speech.

You would use this with:

• close friends
• younger people
• someone you speak casually with
• diary or inner-thought style

A polite version would be:

지난번에 만난 선생님을 오늘 다시 봐서 정말 반가웠어요.

That would sound more appropriate in many everyday situations.

They are similar, but not exactly identical.

• 만난 선생님 is a straightforward, neutral way to say the teacher I met
• 만났던 선생님 can feel a bit more retrospective, as if recalling a previous experience or memory

In this sentence, 만난 선생님 sounds simple and natural.

So yes, they are close in meaning, but 만난 is the more neutral choice here.

Korean does not have articles like a and the.

Instead, whether something is specific or not is understood from context.

Here, 지난번에 만난 선생님 is already clearly specific, so in English we naturally translate it as:

the teacher I met last time

Even though there is no separate Korean word for the.

A very literal breakdown is:

지난번에 — last time
만난 — met
선생님을 — the teacher + object marker
오늘 — today
다시 — again
봐서 — because I saw / seeing
정말 — really
반가웠어 — was glad

So the structure is basically:

[the teacher I met last time] [today] [again] [saw, so/because] [really was glad]

Natural English rearranges this as:

I was really glad to see the teacher I met last time again today.

Korean often builds the sentence step by step and puts the main feeling or conclusion near the end.