chinguga olhae daehageul joreophaeyo.

가 is the subject marker, while 는 is the topic marker.

In 친구가 올해 대학을 졸업해요, 친구가 simply marks friend as the subject:

• The friend is graduating from college this year.

Using 는 would change the nuance a little:

• 친구는 올해 대학을 졸업해요 = As for my/the friend, they are graduating this year, possibly with some contrast or topic-setting feeling.

So 가 is a very natural choice when you are just stating the fact.

Korean often leaves out possessives like my, your, or his/her when the meaning is clear from context.

So 친구가 can mean:

• my friend
• a friend
• the friend

depending on the situation.

If you want to say my friend explicitly, you can say:

• 제 친구가 (polite)
• 내 친구가 (casual)

But in everyday Korean, leaving it out is very common.

No. 친구 is gender-neutral.

It just means friend, regardless of whether the person is male or female. If Korean speakers want to specify gender, they usually add extra words, but 친구 by itself does not tell you.

Time words in Korean often appear without a particle, especially in everyday speech.

So 올해 by itself naturally means:

• this year

You could sometimes see a particle in other contexts, but with common time expressions like these, no particle is very normal:

• 오늘 = today
• 내일 = tomorrow
• 올해 = this year
• 작년 = last year

So 올해 대학을 졸업해요 is completely natural.

This is a very common point of confusion.

In Korean, 졸업하다 usually takes the school as its object, so Korean says literally something like:

• graduate college/university

That is why you use 을/를:

• 대학을 졸업하다
• 고등학교를 졸업하다

So even though English uses from, Korean normally uses the object marker.

졸업해요 is the polite present-style form of 졸업하다.

Breakdown:

• 졸업 = graduation
• 하다 = to do
• 졸업하다 = to graduate
• 졸업해요 = polite conversational form

This -해요 ending is part of the very common 해요-style speech level, which is polite but not overly formal.

Compare:

• 졸업해요 = polite everyday speech
• 졸업합니다 = more formal
• 졸업해 = casual/informal

In Korean, the present form often covers future events too, especially when the event is planned, expected, or understood from context.

So 올해 대학을 졸업해요 can naturally mean:

• is graduating from college this year
• will graduate from college this year

Korean does have explicit future forms, but they are not always necessary. If the time word 올해 already tells you when it will happen, the present-style form sounds very natural.

Yes. Both are possible.

• 대학 = college / university
• 대학교 = university

In everyday Korean, 대학 is often used very naturally for college/university in general.
대학교 can sound a little more explicit.

So:

• 대학을 졸업해요
• 대학교를 졸업해요

are both understandable and natural, depending on context.

Yes. Korean word order is more flexible than English, especially with time expressions.

The original sentence:

• 친구가 올해 대학을 졸업해요

could also appear as:

• 친구가 대학을 올해 졸업해요

But the original version is more neutral and natural for many situations.

A good basic pattern is:

• subject + time + object + verb

So this sentence is a very standard example of that order.

No, it would not be wrong. It just has a different nuance.

• 친구가 올해 대학을 졸업해요 = neutral statement about the subject
• 친구는 올해 대학을 졸업해요 = as for the friend, they graduate this year

Using 는 can sound like:

• you are introducing friend as the topic, or
• you are contrasting the friend with someone else

For example:

• 저는 아직 학생이에요. 친구는 올해 대학을 졸업해요.
  I’m still a student. My friend graduates this year.

So both are possible, but 가 and 는 do not feel exactly the same.

It is polite conversational Korean.

Because the verb ends in -해요, it is appropriate for:

• everyday polite conversation
• talking to someone you do not speak casually with
• most normal social situations

It is not:

• very formal: 졸업합니다
• very casual: 졸업해

So this is a good, standard sentence style for learners to know.