gabangeun uija araee duseyo.

은/는 is the topic marker, while 을/를 is the object marker.

So 가방은 means something like as for the bag or the bag, .... It can sound slightly contrastive, depending on context.

• 가방은 의자 아래에 두세요.
  = As for the bag, put it under the chair.
• 가방을 의자 아래에 두세요.
  = Put the bag under the chair.

In many everyday situations, 가방을 may sound more neutral if you are simply giving an instruction about the bag. Using 가방은 can make the bag the topic, especially if other things are being discussed too.

It breaks down like this:

• 의자 = chair
• 아래 = below / under
• 에 = a particle marking the location or destination of placement

So 의자 아래에 means under the chair.

In Korean, when you say where something is placed, 에 is commonly used with verbs like 두다:

• 책상 위에 두세요. = Put it on the desk.
• 상자 안에 두세요. = Put it inside the box.

The particle 에 shows the place where something ends up or is placed.

Since 두다 means to put / place / leave, Korean normally marks the destination/location with 에:

• 의자 아래에 두세요 = Put it under the chair
• 가방 안에 넣으세요 = Put it in the bag

In casual speech, people sometimes drop particles, so you may hear 의자 아래 두세요, but 의자 아래에 두세요 is the full standard form.

두세요 comes from the verb 두다, which can mean:

• to put
• to place
• to leave

Here, it means please put or please leave.

The ending -세요 is a polite way to tell someone to do something. So 두세요 is a polite instruction or request.

Examples:

• 여기에 두세요. = Please put it here.
• 문 앞에 두세요. = Please leave it in front of the door.

Korean normally puts the verb at the end.

A very common Korean sentence pattern is:

topic/object + place + verb

So:

• 가방은 = the bag
• 의자 아래에 = under the chair
• 두세요 = please put it

Literally, the order is closer to:

As for the bag, under the chair put it.

That is normal in Korean.

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

In this sentence, the understood subject is you:

• (당신은) 가방은 의자 아래에 두세요.

But Korean usually does not say 당신은 in this kind of instruction. It sounds more natural to omit it.

So the sentence naturally just means:

Please put the bag under the chair.

Yes, often you can.

• 두다 = to put/place/leave
• 놓다 = to put down/place

So 가방은 의자 아래에 놓으세요 is also understandable and natural.

The difference is subtle:

• 두다 often suggests placing something somewhere and leaving it there
• 놓다 often focuses more on the act of setting it down

In many everyday situations, both work.

No. Korean does not use articles like the or a/an.

So 가방 can mean:

• a bag
• the bag
• bags (in some contexts)

The exact meaning depends on context.

That means 가방은 의자 아래에 두세요 could be understood as:

• Put the bag under the chair
• Put a bag under the chair

But in real situations, the context usually makes it clear which meaning is intended.

Yes. 밑에 is also very common for under.

• 의자 아래에 = under the chair
• 의자 밑에 = under the chair

For physical objects, especially things like chairs, tables, and desks, 밑에 often sounds very natural.

A rough difference:

• 아래 = below / underneath, broader meaning
• 밑 = under / beneath, often for physical space directly underneath something

But in this sentence, both are fine:

• 가방은 의자 아래에 두세요.
• 가방은 의자 밑에 두세요.