chinguga jigeum jihacheoreul taneun geos gatayo.

Both are possible, but they give slightly different nuance.

• 친구가 marks friend as the subject being identified or focused.
  • It can sound like It seems that my friend is taking the subway right now.
• 친구는 would mark friend as the topic.
  • That can sound more like As for my friend, it seems they’re taking the subway right now.

In this sentence, 가 feels natural because the speaker is making an observation or guess specifically about the friend.

지금 means now / right now.

In Korean, adverbs like 지금 are fairly flexible in position, as long as they appear before the main predicate. So these are all possible:

• 친구가 지금 지하철을 타는 것 같아요.
• 지금 친구가 지하철을 타는 것 같아요.
• 친구가 지하철을 지금 타는 것 같아요.

The original version sounds very natural. Putting 지금 before 지하철을 타는 clearly tells you the action is happening now.

Because 타다 usually takes a direct object, and 지하철 is that object here.

• 지하철을 타다 = to ride / take the subway
• 버스를 타다 = to ride / take the bus
• 택시를 타다 = to take a taxi

So 을/를 marks the thing being ridden or taken.

It can correspond to several English verbs depending on context.

With transportation, 타다 most often means:

• to ride
• to take
• sometimes to get on, depending on the situation

So 지하철을 타다 can be translated as:

• ride the subway
• take the subway
• sometimes be getting on the subway

In this sentence, the exact English wording depends on context, but the Korean itself is broad enough to cover the general idea of using the subway.

-는 것 같아요 means it seems like... / I think... / it looks like...

It is used when the speaker is not stating something as a certain fact, but as an impression, guess, or inference.

So:

• 타는 것 같아요 = it seems like (someone) is riding / taking
• Full sentence: 친구가 지금 지하철을 타는 것 같아요 = It seems like my friend is taking the subway right now

This pattern is very common in everyday Korean when you want to sound less absolute.

Because 타는 connects to a present/ongoing action, while 탄 usually connects to a completed/past action.

• 타는 것 같아요 = it seems like they are taking / riding
• 탄 것 같아요 = it seems like they took / got on / have ridden

So if the meaning is about something happening now, 타는 것 같아요 is the right form.

Good question. Both can work, but they are slightly different.

• 타는 것 같아요 is a general present-style description.
• 타고 있는 것 같아요 emphasizes the action is in progress right now.

So:

• 친구가 지금 지하철을 타는 것 같아요 = It seems my friend is taking the subway now
• 친구가 지금 지하철을 타고 있는 것 같아요 = It seems my friend is currently on the subway / in the middle of riding it

In many everyday situations, 타는 것 같아요 is natural and sufficient.

Yes, it usually expresses some degree of uncertainty or softening.

It often means the speaker is:

• making a guess
• drawing a conclusion from evidence
• speaking less directly
• avoiding sounding too definite

So this sentence does not sound like a firm statement such as:

• 친구가 지금 지하철을 타요. = My friend is taking the subway now.

Instead, it sounds more like:

• I think my friend is taking the subway now
• It looks like my friend is taking the subway now

Because 같아요 is in the polite, non-formal speech style, which is very common in conversation.

• 같아요 = polite everyday style
• 같아 = casual style
• 같습니다 = formal style

So you could have:

• 친구가 지금 지하철을 타는 것 같아요. — polite
• 친구가 지금 지하철을 타는 것 같아. — casual
• 친구가 지금 지하철을 타는 것 같습니다. — formal

Yes. Korean often does not use articles like English a or the, and it also often leaves out possessives like my when they are understood from context.

So 친구가 could mean:

• my friend
• a friend
• the friend

In many everyday contexts, English translation uses my friend because that is what sounds natural.

Yes, very often.

If the context already makes it clear who you mean, Korean can omit 친구가:

• 지금 지하철을 타는 것 같아요.

This could mean:

• I think they’re taking the subway now
• It seems like my friend is taking the subway now

Korean frequently drops subjects and topics when they are understood from context.

The basic structure is:

• 친구가 = subject
• 지금 = adverb (now)
• 지하철을 = object
• 타는 것 같아요 = predicate (seems to be taking)

So Korean is generally Subject-Object-Verb, and the main verb-related part comes at the end.

A rough breakdown is:

• 친구가 — friend + subject marker
• 지금 — now
• 지하철을 — subway + object marker
• 타는 — riding / taking
• 것 같아요 — it seems / I think

It can be used with both verbs and adjectives, but the form changes a little.

With verbs:

• 오는 것 같아요 = it seems like (someone) is coming
• 먹는 것 같아요 = it seems like (someone) is eating

With adjectives:

• 큰 것 같아요 = it seems big
• 바쁜 것 같아요 = it seems busy

So in your sentence, 타는 것 같아요 is the verb version.

Yes, very naturally.

For example, the speaker might say this because:

• the friend texted that they are on the way
• the friend’s location suggests they are near a station
• the speaker heard something that makes it likely

것 같아요 often implies I’m not 100% sure, but based on what I know, this seems true. That is one of the most important nuances of the sentence.