gugeneun huchureul jogeumman neohneun ge johayo.

국 means soup here.

• 에 marks the place or target something goes into, so 국에 means in the soup or into the soup.
• 는 is the topic/contrast marker.

So 국에는 is not just in the soup, but more like:

• as for the soup
• in soup, at least
• when it comes to soup

The 는 often adds a slight contrast. It can suggest something like:

• In soup, it’s best to add only a little pepper
  (maybe unlike some other dishes)

후추 means pepper, and it is the thing being added, so it is the direct object of 넣다 (to put in / to add).

That is why it takes 를:

• 후추를 넣다 = to add pepper

If you used 후추가, it would change the structure and meaning. 가 marks the subject, but here pepper is not the subject; it is the thing being put into the soup.

조금 means a little or a small amount.

만 means only.

So:

• 조금만 = only a little
• just a small amount

This is stronger than just 조금. Compare:

• 조금 넣어요 = Add a little
• 조금만 넣어요 = Add only a little

The 만 emphasizes that you should not add much.

넣는 게 좋아요 is a very common Korean way to say it is good to do X or you should do X.

Breakdown:

• 넣다 = to add / to put in
• 넣는 것 = the act of adding
• 것이 becomes 게 in casual natural speech/writing
• 좋아요 = is good

So:

• 넣는 것이 좋아요
• shortened to 넣는 게 좋아요

This literally means something like the act of adding ... is good, but in natural English it usually means:

• It’s best to add ...
• You should add ...

-는 게 좋아요 is often used for advice, recommendations, or what is preferable.

So this sentence is not a hard command. It sounds more like:

• It’s best to add only a little pepper to soup
• You should only add a little pepper to soup

It is softer than an order like:

• 조금만 넣으세요 = Please add only a little

So -는 게 좋아요 is useful when giving gentle advice.

Yes, 국에 후추를 조금만 넣는 게 좋아요 is also grammatically correct.

The difference is mainly nuance:

• 국에 = simply in the soup
• 국에는 = as for soup / in soup, specifically

Using 는 adds topic or contrast. It can feel like the speaker is saying:

• For soup, only a little pepper is best
• maybe implying that other foods might be different

So 국에는 sounds a bit more context-aware or contrastive.

Yes, 국 can mean different things depending on the word and context.

In this sentence, 국 means soup.

That is a native Korean word often seen in food names, such as:

• 미역국 = seaweed soup
• 콩나물국 = bean sprout soup

There is also 국 related to country/nation, but that usually appears in words like:

• 한국 = Korea
• 중국 = China
• 외국 = foreign country

Here, because of 후추를 넣다 (add pepper) and the context of cooking, 국 clearly means soup.

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

So this sentence does not explicitly say:

• I
• you
• we
• one

But the meaning is still natural. Depending on context, it could mean:

• You should add only a little pepper to soup
• It’s best to add only a little pepper to soup
• When making soup, adding only a little pepper is best

Omitting the subject is extremely common in Korean.

Yes, 좋아요 is a polite present-style form, and 넣는 게 좋아요 is a natural conversational expression.

Compare:

• 넣는 게 좋아요 = polite, common, conversational
• 넣는 것이 좋아요 = same meaning, slightly less contracted
• 넣는 것이 좋습니다 = more formal

So 게 is just the shortened spoken/written form of 것이, and 좋아요 is less formal than 좋습니다.

All are correct; the original sentence sounds natural and everyday.

In natural pronunciation, 국에는 is pronounced roughly like 구게는.

That is because the final consonant ㄱ in 국 links to the following vowel in 에.

So:

• written: 국에는
• natural pronunciation: 구게는

This kind of sound linking is very common in Korean pronunciation.