После прогулки мы ели арбуз и дыню, а потом ещё съели по одному абрикосу.

Because после requires the genitive case.

• прогулка = walk, stroll
• Genitive singular: прогулки

So:

• после прогулки = after the walk / after a walk

This is a very common pattern:

• после урока = after the lesson
• после работы = after work
• после обеда = after lunch

Ели is the past tense plural form of есть in the imperfective sense, meaning to eat.

Here is the pattern:

• я ел / ела
• ты ел / ела
• он ел
• она ела
• мы ели
• вы ели
• они ели

Because the subject is мы (we), the verb must be plural: ели.

This is one of the most important things in the sentence: aspect.

• ели = imperfective
• съели = perfective

In this sentence:

• мы ели арбуз и дыню suggests the action as a process or general event: we were eating / we ate watermelon and melon
• потом ещё съели по одному абрикосу presents the action as completed: then we ate one apricot each

So the speaker first describes one eating event, then adds another completed action.

A simple way to feel the contrast:

• ели = the activity of eating
• съели = ate up / finished eating

Because арбуз is the accusative singular, and for an inanimate masculine noun, the accusative looks the same as the nominative.

• Nominative: арбуз
• Accusative: арбуз

Since есть / ели takes a direct object, арбуз is in the accusative.

Compare:

• Я вижу стол. → стол stays the same because it is inanimate masculine
• Я вижу брата. → брата changes because it is animate masculine

So:

• ели арбуз = ate watermelon

Because дыня is a feminine noun, and its accusative singular changes form.

• Nominative: дыня
• Accusative: дыню

Since it is also the direct object of ели, it must be accusative:

• ели дыню = ate melon

This is a regular pattern for many feminine nouns ending in -а / -я:

• книга → книгу
• машина → машину
• неделя → неделю

Because they belong to different noun types, even though both are direct objects.

Both are in the accusative singular, but Russian shows accusative differently depending on gender and animacy:

• арбуз = masculine, inanimate → accusative looks like nominative
• дыня = feminine → accusative has its own ending, дыню

So the difference is not because one has a different function. They have the same function, but different declension patterns.

Потом means then / afterwards.

The conjunction а here links the two parts of the sentence. In many contexts, а can mean:

• and
• while
• but

Here it is best understood as a natural transition:

• ..., а потом ... = ..., and then ...

It helps move the story forward from one action to the next.

Here ещё means something like:

• also
• in addition
• more
• on top of that

So:

• а потом ещё съели... = and then we also ate... / and then we had another...

It adds the idea that the apricots came after the watermelon and melon, as an extra thing.

По одному means one each.

So:

• съели по одному абрикосу = ate one apricot each

This is a very common distributive pattern in Russian:

• по одному яблоку = one apple each
• по два билета = two tickets each
• по чашке чая = a cup of tea each

The idea is that the amount is distributed among the people involved.

Since the subject is мы, the meaning is that each person ate one apricot.

After по, Russian often uses a special distributive construction. With один, you get the dative singular:

• одному абрикосу

Both words are in the dative singular here:

• одному = dative singular of один
• абрикосу = dative singular of абрикос

So the phrase literally has the structure by one apricot, but the real meaning is one apricot each.

This is something learners usually just memorize as a common pattern:

• по одному... = one each

Because in the expression по одному абрикосу, the noun is in the dative singular.

• Nominative: абрикос
• Genitive: абрикоса
• Dative: абрикосу

So:

• по одному абрикосу = one apricot each

This is not the normal direct-object pattern anymore. The whole phrase is governed by по in this distributive meaning.

Yes. Depending on context, ели can be translated in more than one way.

Possible translations include:

• we ate watermelon and melon
• we were eating watermelon and melon

Russian imperfective past does not map perfectly onto one English tense. It can describe:

• an ongoing process
• a repeated action
• a general fact
• simply an event viewed without focus on completion

In this sentence, the natural English translation is often just we ate watermelon and melon, even though the Russian verb is imperfective.

Russian has no articles like a or the.

So:

• после прогулки can mean after a walk or after the walk
• по одному абрикосу can mean one apricot each

The exact interpretation comes from context.

Russian speakers rely on:

• context
• word order
• shared knowledge
• modifiers, if needed

If the speaker wanted to be more specific, they could add words to make that clearer, but often Russian simply leaves it understood.

The word order is natural, but not the only possibility.

Current order:

• После прогулки = sets the time first
• мы ели арбуз и дыню = main event
• а потом ещё съели по одному абрикосу = next event

This order sounds very natural because it presents the story step by step:

1. after the walk
2. we ate watermelon and melon
3. then we also ate one apricot each

Russian word order is more flexible than English, but changing it often changes emphasis rather than basic meaning.