После супа дети долго ели крекеры, а я доела свой тёплый тост.

Because после requires the genitive case.

• суп = nominative form
• супа = genitive singular

So:

• после супа = after the soup / after soup

This is a very common pattern in Russian:

• после урока = after the lesson
• после работы = after work
• после дождя = after the rain

So the important thing to remember is: после + genitive.

Yes. Дети is the irregular plural of ребёнок (child) in the meaning children.

So:

• ребёнок = child
• дети = children

In this sentence, дети is the subject, so it is in the nominative plural.

Because the subject is plural, the verb also becomes plural:

• дети ели = the children were eating / ate

Ели is the past tense plural of есть (to eat).

Russian past tense agrees with the subject in gender and number:

• я ел = I ate (male speaker)
• я ела = I ate (female speaker)
• он ел = he ate
• она ела = she ate
• они ели = they ate

Since дети is plural, the verb is plural too:

• дети ели = the children ate / were eating

This is a very important aspect contrast.

• ели is from the imperfective verb есть
• доела is from the perfective verb доесть

Here the sentence contrasts two kinds of actions:

1. дети долго ели крекеры
   This focuses on the process/duration: they were eating crackers for a long time.

2. я доела свой тёплый тост
   This focuses on the completion: I finished eating my toast.

So the imperfective ели works well with долго (for a long time), while perfective доела shows that the action reached its endpoint.

Not quite. Доела means finished eating or ate the rest of.

It comes from:

• есть = to eat
• доесть = to finish eating

The prefix до- often gives the idea of reaching the end of something.

So:

• Я ела тост = I was eating / ate toast
• Я доела тост = I finished the toast

In this sentence, доела strongly suggests that the speaker had already started eating the toast earlier and then finished it.

Because the speaker is female.

In Russian, past tense singular verbs show gender:

• доел = finished eating (male)
• доела = finished eating (female)
• доело = finished eating (neuter, rarely used with people)

So:

• я доел = I finished eating (said by a man)
• я доела = I finished eating (said by a woman)

This sentence tells us the speaker is female.

Russian usually prefers свой when the possessor is the same as the subject of the clause.

Here the subject is я, and the toast belongs to me, so Russian naturally uses свой:

• я доела свой тост = I finished my toast

This sounds more natural than мой in most cases.

A useful rule:

• use свой when it refers back to the subject
• use мой / твой / его etc. when you specifically want to contrast or emphasize ownership, or when it does not refer to the subject

Compare:

• Я взял свою книгу. = I took my book.
• Я взял твою книгу. = I took your book.

Because крекеры is the accusative plural, and for inanimate masculine nouns, the accusative plural is the same as the nominative plural.

Singular:

• крекер = a cracker

Plural:

• крекеры = crackers

After a verb like ели (ate), the thing being eaten is the direct object, so it normally goes in the accusative case:

• ели крекеры = ate crackers

Because крекеры is inanimate, its accusative plural looks the same as the nominative plural.

For the same basic reason: тост is an inanimate masculine noun, and in the accusative singular, it looks the same as the nominative singular.

So:

• nominative: тёплый тост
• accusative: тёплый тост

That is why the whole object phrase stays:

• доела свой тёплый тост

If it were an animate masculine noun, the accusative would usually match the genitive instead.

Долго means for a long time.

So:

• дети долго ели крекеры = the children were eating crackers for a long time

It fits very naturally with the imperfective verb ели, because imperfective aspect often describes a process, duration, or ongoing activity.

Compare:

• долго ели = were eating for a long time
• съели = ate up / finished eating

So долго helps show that the children’s eating is being viewed as an extended activity, not just a completed result.

А often marks a contrast or a switch to a different subject/topic.

Here it means something like:

• while / whereas / and as for
• sometimes close to but, depending on context

So:

• дети долго ели крекеры, а я доела свой тёплый тост
  = The children ate crackers for a long time, while/as for me, I finished my warm toast.

Why not и?

• и simply adds another fact: and

Why not но?

• но is a stronger but, usually for a clearer contradiction

Here а works well because the sentence contrasts:

• the children with
• me

and also contrasts:

• were eating for a long time with
• finished eating

No, Russian word order is fairly flexible, but different orders change the emphasis.

The given sentence is natural and neutral:

• После супа дети долго ели крекеры, а я доела свой тёплый тост.

You could also say:

• После супа долго ели крекеры дети, а я доела свой тёплый тост.
  This is more marked and sounds less neutral.

• Я доела свой тёплый тост, а дети долго ели крекеры.
  This changes the information flow and puts the speaker first.

Russian word order often depends on what is already known and what is being emphasized. The original version is a very normal, natural way to say it.

It can mean either one in English, depending on context.

Russian has no articles like a or the, so супа by itself does not tell you whether English should use the.

So после супа could be translated as:

• after soup
• after the soup
• after having soup

In many everyday contexts, after soup sounds most natural in English, especially if we are talking about a meal course.

Yes, it is understandable and natural enough. It means warm toast.

• тёплый = warm
• тост = toast

The adjective agrees with the noun:

• masculine singular nominative/accusative inanimate:
  • тёплый тост

A learner should mainly notice the agreement pattern here:

• adjective + noun both match in gender, number, and case

So:

• свой тёплый тост = my own warm toast / my warm toast

Yes, but the meaning would change.

• дети долго ели крекеры = the children were eating crackers for a long time
• дети съели крекеры = the children ate up the crackers / finished the crackers

With съели, the focus would be on the result: the crackers were finished.

With ели, the focus is on the activity itself, especially because of долго.

So the sentence is carefully chosen:

• ели for duration
• доела for completion

That contrast is very typical and useful in Russian.