seunggangjange sarami manhaseo da-eum jihacheoreul gidaryeoyo.

승강장 means platform, especially a train or subway platform.

Yes, it is similar to 플랫폼, but 승강장 is the standard native/Korean-based word, while 플랫폼 is a loanword from English. In everyday transit announcements and signs, 승강장 is very common.

So 승강장에 means on the platform or more literally at the platform.

Here, 에 marks the location where a state or existence is described.

In 승강장에 사람이 많아요, the idea is:

• At the platform / On the platform
• there are many people

Because 많다 describes a state, 에 is natural.

Compare:

• 승강장에 사람이 많아요. = There are many people on the platform.
• 승강장에서 기다려요. = I wait on the platform.

So:

• 에 is often used with existence/state ideas like 있다, 없다, 많다
• 에서 is often used for actions happening at a place

Because 많다 works with a subject, not a direct object.

So in 사람이 많다:

• 사람이 = people are
• 많다 = many / numerous

Korean treats this as people are many, not someone has many people.

That is why 이/가 is used, not 을/를.

많아서 is 많다 + -아서, and it means because there are many or since there are a lot.

So:

• 많다 = to be many
• 많아서 = because there are many / since it is crowded with people

In the sentence, it gives the reason for the next action:

• 승강장에 사람이 많아서 = Because there are a lot of people on the platform
• 다음 지하철을 기다려요 = I wait for the next subway

Here -아서/-어서 connects two clauses and shows reason/cause.

Structure:

• reason + -아서/-어서
• result/action

So this sentence is:

• 승강장에 사람이 많아서
• 다음 지하철을 기다려요

Meaning:

• Because there are many people on the platform, I’m waiting for the next subway.

This ending can also sometimes simply connect events, but here it clearly expresses because.

Korean often leaves out the subject when it is obvious from context.

So 기다려요 can mean:

• I wait
• I am waiting
• we wait
• sometimes even you wait, depending on context

In a sentence like this, the natural interpretation is I’m waiting.

Also, Korean present tense often covers both simple present and present progressive in English, depending on context.

Literally, 다음 지하철 means the next subway.

In natural English, this often means:

• the next subway train
• the next train

Because 지하철 can refer to the subway system, a subway ride, or a subway train depending on context.

So in this sentence, it clearly means the next arriving subway train.

Because 기다리다 takes the thing waited for as a direct object in Korean.

So:

• 지하철을 기다려요 = wait for the subway
• 친구를 기다려요 = wait for a friend
• 버스를 기다려요 = wait for the bus

This is different from English, which uses wait for. Korean uses the verb directly with 을/를.

Very close, yes.

승강장에 사람이 많아서 literally means because there are many people on the platform, but in natural English that often becomes:

• because the platform is crowded
• because there are too many people on the platform

So the Korean expression describes the situation by focusing on many people being there, rather than using a single adjective like crowded.

Korean often does not mark plural when the meaning is already clear.

So:

• 사람이 많아요 already clearly means there are many people
• adding 들 is possible, but not necessary

You may hear:

• 사람이 많아요
• 사람들이 많아요

Both can work, but the version without 들 is very natural and common.

기다려요 is in the 해요체 style, which is polite and commonly used in everyday conversation.

It is:

• polite enough for most daily situations
• less formal than 기다립니다
• more polite than plain 기다려

So this sentence sounds natural in normal polite speech.

No, that would be unnatural here.

You need 승강장에 사람이 많아서 because the meaning is:

• At/on the platform, there are many people

If you say 승강장이, then 승강장 becomes the subject, which does not fit well with 사람이 많다 in this structure.

The natural pattern is:

• place + 에
• noun + 이/가 많다

Example:

• 교실에 학생이 많아요. = There are many students in the classroom.
• 길에 차가 많아요. = There are many cars on the road.

Korean usually puts the reason first and the main action later.

So the sentence is organized like this:

• 승강장에 = on the platform
• 사람이 많아서 = because there are many people
• 다음 지하철을 = the next subway
• 기다려요 = am waiting for

More literally:

• On the platform people are many, so the next subway I wait for.

Natural English rearranges this to:

• There are a lot of people on the platform, so I’m waiting for the next subway.

That difference in word order is very normal between Korean and English.