geuraeseo dasi paireul yeolgo sajin du jangeul cheombuhaesseo.

그래서 means so, therefore, or as a result. It connects this sentence to something said earlier.

It tells you that what happens here is the consequence of a previous situation. In other words, the speaker is not starting a brand-new idea—they are continuing a story or explanation.

For example:

• Something went wrong.
• 그래서 다시 파일을 열고 사진 두 장을 첨부했어.

So 그래서 is functioning as a sentence connector.

다시 means again. In this sentence, it most naturally modifies the action of opening the file:

• 다시 파일을 열고 = opened the file again

Because Korean adverbs are flexible, 다시 can sometimes feel like it applies to the whole sequence of actions, but here the most direct reading is that the speaker reopened the file and then attached the photos.

The -을 is the object particle. It marks 파일 as the direct object of the verb 열고.

So:

• 파일 = file
• 파일을 = the file / a file, marked as the thing being opened

Korean often drops particles in casual speech, but in a normal written sentence like this, keeping -을 is natural and clear.

열고 is the verb 열다 (to open) plus -고, which links it to the next action.

Here, -고 means something like:

• and
• then
• and after that

So:

• 파일을 열고 사진 두 장을 첨부했어
  = I opened the file and attached two photos

Why not 열었고?

Because in Korean, when two actions are connected in a sequence, it is very common for only the final verb to carry the tense clearly. The earlier verb often appears in the plain connective form:

• 열고 ... 첨부했어

This is completely normal. The past-time meaning is understood from the final verb 첨부했어.

Not always, but in this sentence it strongly suggests a sequence:

1. open the file
2. attach two photos

The connector -고 can simply mean and, but when it joins action verbs like these, it often implies that one action happened and then the next one happened.

So here it is natural to understand it as opened the file and then attached...

Korean uses counters for counted nouns, and 장 is the counter used for flat items such as:

• paper
• tickets
• cards
• photos

So:

• 사진 두 장 = two photos

You may hear 두 개 in casual speech, and people would still understand it, but 장 is the more natural and precise counter for photos.

In Korean, the common pattern is:

noun + number + counter

So:

• 사진 두 장
• 책 세 권
• 사과 한 개

That is why 사진 두 장을 sounds natural.

While Korean word order can sometimes vary for emphasis, 두 장 사진 is not the normal neutral pattern here.

The base form is 첨부하다, which means to attach.

It breaks down like this:

• 첨부하다 = to attach
• 첨부했어 = attached / did attach

This is the casual past form. The formation is:

• 첨부하-
• -였어 / 했어 past casual ending

With 하다 verbs, this becomes 했어:

• 첨부하다 → 첨부했어

첨부했어 is in the casual / intimate polite-neutral style, often called 반말 when used without polite endings.

It would be natural:

• with friends
• with younger people
• in diaries
• in casual messages
• when talking to yourself

A more polite version would be:

• 그래서 다시 파일을 열고 사진 두 장을 첨부했어요.

A more formal written or business-like version could be:

• 그래서 다시 파일을 열고 사진 두 장을 첨부했습니다.

This is a very common Korean pattern.

When multiple actions are linked together, earlier verbs often appear in a connective form, and the final verb carries the tense and sentence ending.

So:

• 열고 = open and...
• 첨부했어 = attached

Even though 열고 itself is not visibly marked as past, the whole sequence is understood as past because the final verb is in the past.

English often marks both ideas more explicitly, but Korean does not need to.

The subject is omitted because Korean frequently leaves out subjects when they are obvious from context.

In this sentence, the understood subject is probably I, because the final verb style and the context suggest the speaker is describing their own action:

• (나는) 그래서 다시 파일을 열고 사진 두 장을 첨부했어.

But Korean does not need to say 나는 unless there is a reason to emphasize it, contrast it, or clarify who did it.

Yes, in many contexts you could say:

• 그래서 다시 파일을 열어서 사진 두 장을 첨부했어.

This can sound a little more like opened the file and then / by doing that attached...

The difference is small here:

• -고 = simple connection, neutral and common
• -어서 = can sound a bit more connected in process or result

In this sentence, -고 is very natural and straightforward.

No, 파일 is a loanword from English file.

Korean has many loanwords, especially for technology and office-related vocabulary. The pronunciation is adapted to Korean sound patterns:

• file → 파일

This is completely normal Korean vocabulary, even though its origin is English.

The particle -을 attaches to the entire object phrase, not just to the counter by itself.

The full object is:

• 사진 두 장

Then the object particle is added:

• 사진 두 장을

So the speaker is marking two photos as the thing that was attached.

This is standard Korean structure.

The grammar is natural, but the ending 첨부했어 is casual, so it would not usually be appropriate in a professional email unless the relationship is very informal.

For work or polite communication, you would normally use:

• 그래서 다시 파일을 열고 사진 두 장을 첨부했어요.
• 그래서 다시 파일을 열고 사진 두 장을 첨부했습니다.

So the sentence itself is natural, but the level of politeness depends on the situation.