Na rynku kupiliśmy awokado i morele, a potem zjedliśmy gofra z dżemem.

Because na is the normal preposition here, and rynek becomes rynku in the locative case.

• rynek = market square / marketplace
• na rynku = at the market / in the market square

In Polish, this is the idiomatic way to say it. A learner might expect w rynku, but that is not how this place is usually expressed.

Because a is joining two clauses, and each clause has its own verb:

• kupiliśmy
• zjedliśmy

So Polish punctuation normally requires a comma here:

Na rynku kupiliśmy awokado i morele, a potem zjedliśmy gofra z dżemem.

Here a works a bit like and, especially when moving from one event to the next.

• i = simple and
• a = and / while / and then, often with a slight sense of transition or contrast

In this sentence, a potem sounds very natural for continuing the story: first we bought something, and then we ate something.

Because the sentence describes completed actions.

• kupić = to buy, perfective
• zjeść = to eat up, perfective

So:

• kupiliśmy = we bought
• zjedliśmy = we ate / finished eating

If you said kupowaliśmy or jedliśmy, that would usually suggest an ongoing, repeated, or background action rather than a single completed event.

This is a past-tense ending meaning we did.

So:

• kupiliśmy = we bought
• zjedliśmy = we ate

More exactly, Polish past tense agrees with the subject. -liśmy is the form used for a group that is masculine-personal or mixed. If the speakers were all female, you would normally say:

• kupiłyśmy
• zjadłyśmy

Awokado is a loanword that is usually treated as indeclinable in the singular, so it often keeps the same form in different cases.

That means you can see awokado without any visible ending change even when it is the object of the verb.

Because morele is the plural form of morela.

Here it is the direct object of kupiliśmy, and for non-masculine-personal plural nouns, the accusative plural is the same as the nominative plural.

So:

• singular: morela
• plural: morele

A form like moreli would be genitive plural, not the form needed here.

Because it is the direct object of zjedliśmy, so it must be in the accusative case.

Although gofr is grammatically masculine inanimate, many masculine nouns referring to food take -a in the accusative singular. This is very common in Polish.

For example:

• zjeść banana
• zjeść pączka
• zjeść gofra

So gofra is the normal form here.

Because the preposition z meaning with requires the instrumental case.

So:

• dżem = jam
• z dżemem = with jam

This is a very common pattern in Polish:

• z serem
• z masłem
• z cukrem

One important detail: z can also mean from, but then it usually takes a different case. Here it clearly means with.

Because Polish does not have articles.

So nouns like awokado, morele, and gofra appear without any separate word for a/an/the. The exact meaning is understood from context.

That is why Polish can say simply:

• kupiliśmy awokado
• zjedliśmy gofra

without needing an article.

No, Polish word order is fairly flexible.

Na rynku kupiliśmy awokado i morele puts the location first, as the setting of the sentence. But other orders are also possible, for example:

• Kupiliśmy na rynku awokado i morele
• Awokado i morele kupiliśmy na rynku

These versions can sound slightly different in emphasis, but they are still grammatical. The original sentence starts with Na rynku because it sets the scene nicely.