gabangeul yeoreo bonikka yeogwoni eobseoyo.

Here, 열어 보니까 means something like when I opened it and checked / after opening it, I found that...

It comes from:

• 열다 = to open
• -아/어 보다 = to try doing something, or to do something and see
• -니까 = when / since / after doing

So:

• 열어 보다 = to open it and see / to try opening it
• 열어 보니까 = when I opened it and looked, ...

In this sentence, 보다 does not literally mean just to see with the eyes. It helps give the sense of checking or finding out by doing.

So 가방을 열어 보니까 여권이 없어요 feels like:

• I opened the bag and checked, and the passport wasn’t there.

Good question. You will often see both 열어보다 and 열어 보다.

In modern Korean spacing, auxiliary verbs like 보다 are often written separately:

• 열어 보다
• 먹어 보다
• 가 보다

So 열어 보니까 is a very normal spaced form.

That said, learners will also encounter attached forms in dictionaries or informal writing, such as:

• 열어보다
• 먹어보다

Both are commonly understood, but writing them separately is very standard in actual Korean text.

-아/어 보니까 often gives the nuance of:

• the speaker did something directly
• then discovered or realized something as a result

So 열어 보니까 strongly suggests:

• I actually opened it and checked
• then I found out the passport was missing

Compared loosely:

• 열니까 = when I open/opened it
• 열었더니 = I opened it, and then...
• 열어 보니까 = I opened it to check, and found that...

So -어 보니까 is especially natural when the second part is a new discovery.

Because the two nouns play different roles in the sentence.

• 가방을: the bag is the thing being opened, so it takes 을/를, the object marker.
• 여권이: the passport is the thing that does not exist / is not there, so it takes 이/가.

Breakdown:

• 가방을 열다 = to open the bag
• 여권이 없다 = the passport is absent / there is no passport

In Korean, 있다 / 없다 usually take 이/가 for the thing that exists or does not exist.

So:

• 여권이 없어요 = The passport isn’t there.

not:

• 여권을 없어요 ✘

Because the speaker is describing the state discovered at that moment:

• I opened the bag and the passport is not there.

Korean often uses the present tense for a current state, even if that state was discovered after a past action.

So the sequence is:

1. 가방을 열어 보니까 = when I opened the bag and checked
2. 여권이 없어요 = the passport isn’t there

If you said 없었어요, it would sound more like:

• the passport wasn’t there at that past time

That can be possible in some contexts, but 없어요 is very natural if the speaker is reporting the current situation they just discovered.

Because Korean often leaves out subjects when they are obvious from context.

In this sentence, it is easy to understand that the speaker is the one who opened the bag and discovered the passport was missing.

So Korean naturally says:

• 가방을 열어 보니까 여권이 없어요.

instead of:

• 제가 가방을 열어 보니까 여권이 없어요.

Adding 제가 is possible, but usually unnecessary unless you want emphasis, contrast, or clarity.

It can mean either, depending on context.

For example:

• 돈이 없어요 = I don’t have money / there is no money
• 사람이 없어요 = there is no person / no one is here

In 여권이 없어요, the most natural meaning is:

• the passport isn’t there
• the passport is missing
• I don’t have my passport with me

So Korean uses 없다 in a broader way than English. It does not always map neatly to only one English expression.

It can imply that the speaker has just realized the passport is missing, but the sentence itself does not say why.

It only states:

• the speaker opened the bag
• after checking, the passport was not there

So the passport could be:

• lost
• stolen
• left somewhere else
• in another bag
• at home

The sentence reports the discovery, not the cause.

Yes, that is the implied meaning.

Because the first clause says:

• 가방을 열어 보니까 = when I opened the bag and checked

the listener naturally understands that the second clause is about what was or was not found in the bag.

Korean often leaves out information that is clear from context.

If someone wanted to be more explicit, they could say something like:

• 가방 안에 여권이 없어요. = The passport isn’t in the bag.

But in your sentence, that detail is already strongly understood.

없어요 is the polite informal style, often called 해요체.

It is very common in everyday conversation and is appropriate in many situations.

Related forms:

• 없어 = casual
• 없어요 = polite
• 없습니다 = formal

So this sentence sounds polite and natural for normal speech:

• 가방을 열어 보니까 여권이 없어요.

Not always. That is one of the most important things to notice.

-아/어 보다 can mean:

1. try doing something
   • 먹어 봐요. = Try eating it.
2. do something and see / check
   • 문을 열어 봐요. = Open the door and see.
3. In forms like -아/어 보니까, it often means after doing it, I found/realized...
   • 읽어 보니까 재미있어요. = After reading it, I found it interesting.

In your sentence, it is not really about trying in the English sense. It is more about checking and discovering.

Yes, you could, but the nuance changes a little.

• 가방을 열어 보니까 여권이 없어요.

  • I opened the bag and checked, and then discovered the passport wasn’t there.
  • Strong sense of discovery after checking.

• 가방을 열었는데 여권이 없어요.

  • I opened the bag, but the passport isn’t there.
  • More neutral connection; it can also carry a mild contrast or disappointment.

So both are possible, but 열어 보니까 is especially good when the speaker is talking about what they found out by looking.

A natural casual version would be:

• 가방을 열어 보니까 여권이 없어.

Changes:

• 없어요 → 없어

Everything else can stay the same.

If speaking very casually, someone might also shorten or reshape the sentence depending on tone, but 가방을 열어 보니까 여권이 없어 is a straightforward casual version.