chinguhante yeopseoneun bonaessjiman soponeun ajik mos bonaesseo.

친구한테 means to a friend.

Here, 한테 marks the recipient of the sending action, so it works like to in English:

• 친구한테 엽서를 보냈어 = I sent a postcard to a friend

A few useful notes:

• 한테 is very common in everyday speech.
• 에게 means the same thing but sounds a bit more formal or written.
• With people, both are common:
  • 친구한테
  • 친구에게

So in this sentence, 친구한테 tells us who received the postcard.

This 는 is doing a contrastive job.

If you just wanted to say I sent a postcard, you would normally use:

• 엽서를 보냈어

But in this sentence, the speaker is comparing two things:

• as for the postcard, I sent it
• as for the package, I still haven’t sent it

So:

• 엽서는 = the postcard, at least / as for the postcard
• 소포는 = the package, though / as for the package

This creates a contrast:

• postcard: sent
• package: not sent yet

That is why 는 is very natural here.

• 엽서 = postcard
• 소포 = package / parcel

So the sentence contrasts sending a small mailed card with sending a package.

-지만 means but, although, or even though, depending on context.

Here:

• 보냈지만 = sent, but...

So the structure is:

• 친구한테 엽서는 보냈지만 = I sent the postcard to my friend, but...
• 소포는 아직 못 보냈어 = I still haven’t been able to send the package

It connects the two clauses and shows contrast.

Because the action of sending the postcard is already completed.

• 보내다 = to send
• 보냈- = past tense stem, sent
• 보냈지만 = sent, but...

The speaker is saying:

• one action is done: the postcard was sent
• the other is not done yet: the package has not been sent yet

So the past tense is necessary for the first clause.

아직 means still or yet.

못 보냈어 literally means couldn’t send or was unable to send.

Together, 아직 못 보냈어 means:

• I still haven’t sent it
• more literally, I still haven’t been able to send it

This often implies that the speaker intended to send it, but for some reason it has not happened yet.

This is a very important distinction.

• 안 보냈어 = I didn’t send it

  • focuses on the fact that the action did not happen
  • may sound like a choice or simple non-performance

• 못 보냈어 = I couldn’t send it / I wasn’t able to send it

  • suggests inability, difficulty, or some preventing circumstance

So in this sentence, 못 보냈어 gives the feeling:

• I intended to send the package, but I haven’t managed to yet

That is slightly different from simply saying I didn’t send it yet.

Korean often uses a past-tense form where English uses the present perfect.

• 못 보냈어 is literally past: couldn’t send / didn’t manage to send
• But with 아직, it naturally means something like:
  • I still haven’t sent it
  • I haven’t been able to send it yet

So the Korean form is past, but the most natural English translation is often present perfect.

Because Korean often omits information that is already understood from context.

The full idea is:

• I sent the postcard to my friend, but I still haven’t sent the package to my friend

But repeating 친구한테 would be unnecessary if the recipient is obviously the same. Korean commonly leaves that kind of thing out.

So the second clause is understood as having the same recipient unless context suggests otherwise.

보냈어 is the casual informal style.

It is used with:

• friends
• family
• people younger than you
• people you are close to

The polite version would be:

• 친구한테 엽서는 보냈지만 소포는 아직 못 보냈어요.

So the sentence as given sounds natural in casual conversation.

Yes.

You could say:

• 친구에게 엽서는 보냈지만 소포는 아직 못 보냈어.

This means the same thing.

The difference is mainly tone:

• 한테 = more conversational
• 에게 = a bit more formal or neutral

In everyday speech, 한테 is very common.

Korean word order is fairly flexible, as long as the particles make the roles clear.

The given sentence is very natural:

• 친구한테 엽서는 보냈지만 소포는 아직 못 보냈어.

You could rearrange parts for emphasis, for example:

• 엽서는 친구한테 보냈지만 소포는 아직 못 보냈어.

This puts a bit more focus on the postcard first.

However, not every rearrangement sounds equally natural, and the original sentence is a very standard, natural order for conversation.