Min søster har købt en rød kjole og sorte bukser i byen.

Because søster is a common-gender noun in Danish, and common-gender nouns take min for my.

• min = used with common-gender nouns
• mit = used with neuter nouns

So:

• min søster = my sister
• mit hus = my house

You have to learn the gender of each noun, because it affects words like en/et, min/mit, and adjective endings.

In Danish, possessives like min, din, hans, vores, etc. usually replace the article.

So Danish says:

• min søster = my sister

not:

• en min søster
• den min søster

This works much like English, where we also say my sister, not the my sister.

Har købt is the present perfect tense, similar to English has bought.

• har = has
• købt = past participle of købe = buy

So:

• Min søster har købt ... = My sister has bought ...

This tense is commonly used in Danish for completed actions that are relevant now, just as in English.

Compare:

• Min søster køber ... = My sister is buying / buys ...
• Min søster købte ... = My sister bought ...
• Min søster har købt ... = My sister has bought ...

Because kjole is a common-gender singular noun, so it takes:

• en as the article
• the adjective in its basic common-gender singular form: rød

So:

• en rød kjole = a red dress

This is a typical pattern:

• en stor bil = a big car
• en ny jakke = a new jacket

There are two things happening here:

1. Bukser is plural

Bukser means trousers/pants, and in Danish it is normally used in the plural.

Because the noun is plural, the adjective must also take the plural form:

• sort = black
• sorte = black, plural/definite form

So:

• sorte bukser = black trousers

2. No article is needed here

In this sentence, sorte bukser means black trousers / some black trousers, so Danish does not need an article before the plural noun here.

Compare:

• en rød kjole = a red dress
• sorte bukser = black trousers / some black trousers

This is normal in Danish and often sounds natural in English too.

Because Danish adjectives change form depending on the noun they describe.

Here is the pattern in a simplified way:

• common-gender singular, indefinite: rød
• plural: røde/sorte, etc.

In your sentence:

• en rød kjole → singular common-gender
• sorte bukser → plural

So the adjective has to agree with the noun.

A few more examples:

• en blå stol = a blue chair
• et blåt hus = a blue house
• blå stole = blue chairs

This is a very common question.

Danish often uses:

• en/et with a singular indefinite noun
• no article with an indefinite plural noun

So:

• en rød kjole = a red dress
• sorte bukser = black trousers / some black trousers

That is similar to English:

• a dress
• trousers or some trousers

So the difference is mainly grammatical number:

• singular: article needed
• plural: article often omitted

I byen literally means in the town/city, but in context it usually means something like:

• in town
• in the city
• downtown, depending on context

So the sentence means she bought the clothes while in town / in the city.

This is a common Danish expression. In many cases, i byen is understood idiomatically rather than very literally.

Because byen is the definite form of by.

• by = town/city
• byen = the town/city

Danish often attaches the definite article to the end of the noun:

• en by = a town/city
• byen = the town/city

In the fixed expression i byen, Danish uses the definite form. English often translates it more naturally as in town rather than in the town.

This is normal Danish main-clause word order:

subject + finite verb + the rest

So:

• Min søster = subject
• har = finite verb
• købt = past participle
• then the objects and adverbial phrase follow

Danish is a V2 language, which means the finite verb is normally in the second position in main clauses.

In this sentence, the subject comes first, so the verb comes next:

• Min søster har købt ...

If another element came first, the verb would still stay in second position:

• I byen har min søster købt en rød kjole og sorte bukser.

That is one of the big differences from English word order.

Yes. Og means and.

It links the two things your sister bought:

• en rød kjole
• sorte bukser

So the sentence says she bought both items.

Danish normally uses bukser as a plural noun, much like English trousers or pants.

So Danish says:

• sorte bukser = black trousers/pants

If you specifically wanted to say a pair of trousers, Danish can say:

• et par bukser

But in ordinary speech, just bukser is very common.

Yes, you often can, but the two forms are not always used in exactly the same way.

• min søster = the most straightforward way to say my sister
• søsteren min = literally the sister of mine, also very natural in Danish

Both are possible, but min søster is often the simpler choice for learners and is very common in neutral statements like this one.

So:

• Min søster har købt ... = completely natural
• Søsteren min har købt ... = also possible, often with a slightly different rhythm or emphasis

Here are the basic forms:

• min = my
• søster = sister
• har = present tense of have
• købt = past participle of købe = to buy
• en = a/an for common-gender nouns
• rød = red
• kjole = dress
• og = and
• sort = black
• bukser = trousers/pants
• i = in
• by = town/city
• byen = the town/city

This is useful because Danish words often change form depending on number, definiteness, or grammar.