yeohaeng gabange chissorirang chiyageul neoheosseo?

Because with the verb 넣다 (to put in / insert / pack into), the place or container that something goes into is usually marked with 에.

So:

• 여행 가방에 = in/into the suitcase
• 칫솔이랑 치약을 = the toothbrush and toothpaste as the thing being put in

A useful pattern is:

• 장소에 + 물건을 넣다
  = put an item into a place/container

For example:

• 가방에 책을 넣었어. = I put a book in the bag.

Here, 이랑 means and.

So:

• 칫솔이랑 치약 = toothbrush and toothpaste

A few useful notes:

• 이랑 / 랑 is a common, informal way to connect nouns.
• After a noun ending in a consonant, you use 이랑.
• After a noun ending in a vowel, you usually use 랑.

Examples:

• 칫솔이랑 치약
• 우유랑 빵

Also, 이랑/랑 can sometimes mean with, depending on context, but in this sentence it clearly means and.

Because 칫솔이랑 치약 works as one combined noun phrase: toothbrush and toothpaste.

In Korean, when two nouns are joined like this, the case particle often goes only once at the end of the whole phrase.

So:

• 칫솔이랑 치약을 넣었어? = natural
• 칫솔을이랑 치약을 = not correct

You can think of it like this:

• [칫솔이랑 치약] + 을

The whole connected phrase is the object of 넣었어.

Because the speaker is asking whether the action has already been completed.

So 넣었어? is literally past tense, something like:

• Did you put it in?
• Have you packed it in?

In Korean, past tense is very commonly used this way when asking if someone has already done something. It often sounds very natural in situations like packing, checking, or confirming.

If you used 넣어?, that would sound more like:

• Are you putting it in?
• Do you put it in?

That is not the intended meaning here.

Because Korean is generally an SOV language: Subject-Object-Verb.

English usually goes:

• Did you put the toothbrush and toothpaste in the suitcase?

Korean usually puts the verb at the end:

• (you) suitcase-in toothbrush-and toothpaste-object put-did?

This is one of the most important word-order differences between English and Korean.

It is omitted.

Korean very often leaves out subjects and objects when they are already understood from context. In this sentence, the subject is naturally understood as you.

So even though 너는 or 당신은 is not written, the meaning is still clear.

This is very normal in Korean. In fact, adding the subject too often can sound unnatural.

In Korean, yes/no questions are often made just by:

• using the normal verb form
• saying it with questioning intonation
• writing a question mark in text

So:

• 넣었어. = statement
• 넣었어? = question

The form itself can stay the same in casual speech. The intonation and punctuation show that it is a question.

No, it is casual speech, often called banmal.

It is natural when speaking to:

• close friends
• younger people
• family members
• someone you speak casually with

A polite version would be:

• 여행 가방에 칫솔이랑 치약을 넣었어요?

That is the same basic sentence, but with the polite ending -어요.

Because Korean often makes compound noun expressions by simply putting nouns together.

So:

• 여행 가방 = literally something like travel bag
• in natural English: suitcase or travel bag

There is no need for a word like of or a possessive marker here.

This kind of noun-noun combination is very common in Korean, for example:

• 학교 건물 = school building
• 커피 잔 = coffee cup
• 여권 사진 = passport photo

Yes. You could also say:

• 칫솔하고 치약을 넣었어?
• 칫솔과 치약을 넣었어?

The difference is mostly style:

• 이랑 / 랑 = casual, conversational
• 하고 = also common and conversational
• 와 / 과 = more formal or written-sounding

In this sentence, 이랑 fits very naturally because 넣었어? is already casual.

With 넣다, it can feel like either in or into in English, depending on how you translate it.

That is because the action involves both:

• the destination/container
• the result of something ending up inside it

So 여행 가방에 넣었어? can naturally become:

• Did you put it in the suitcase?
• Did you put it into the suitcase?

English makes a sharper distinction between in and into than Korean does in many cases.

Yes. 칫솔이랑 치약 presents the toothbrush and toothpaste as a set of items being checked together.

So the speaker is asking whether both were packed.

If the speaker wanted to ask about them separately, they might use separate questions or a different structure. But as written, it is a normal way to ask about both together as part of a packing checklist.