После длинного дня мы поддерживали друг друга и всё равно не ссорились.

Because после requires the genitive case.

• день → genitive singular дня
• длинный → genitive singular masculine/neuter длинного

So:

• nominative: длинный день
• after после: после длинного дня

This is very common in Russian: many prepositions force a specific case.

Yes, после долгого дня would also be very natural.

Both длинный and долгий can refer to time, but there is a slight nuance:

• долгий = long in duration, often the more neutral choice for time
• длинный = literally long, but also used for time, often suggesting that something felt long or was full/exhausting

So:

• после долгого дня = after a long day
• после длинного дня = also after a long day, with a slightly more felt/experienced sense

In everyday speech, both can work here.

Yes, Russian often drops subject pronouns when the meaning is clear from context.

But here мы is useful because the past tense plural form поддерживали could mean either we supported or they supported. Russian past tense shows number and, in the singular, gender, but not person.

So:

• поддерживали = we supported / they supported
• мы поддерживали clearly means we supported

Including мы makes the subject explicit.

Поддерживали is the imperfective past form of поддерживать.

Here the imperfective suggests:

• an ongoing action
• repeated action
• background action over a period of time

So the idea is something like:

• we were supporting each other
• we kept supporting each other

If you used поддержали, that would sound more like a completed, single act of support:

• we supported each other once / successfully supported each other

In this sentence, поддерживали fits better because it describes what was happening over the course of the long day.

Друг друга means each other.

So:

• мы поддерживали друг друга = we supported each other

It is the standard Russian reciprocal expression. You use it when two or more people do something to one another.

Examples:

• Мы видели друг друга. = We saw each other.
• Мы помогали друг другу. = We helped each other.
• Мы говорили друг с другом. = We spoke with each other.

Because the expression друг друга changes by case, depending on the verb or preposition.

With поддерживать, the object is in the accusative. But since this reciprocal expression refers to people, the accusative looks like the genitive form here:

• поддерживать кого? → друг друга

Other cases look different:

• друг другу = to each other
• друг с другом = with each other
• друг о друге = about each other

So in this sentence, друг друга is the correct form after поддерживали.

Here всё равно means something like:

• all the same
• still
• anyway
• despite that

So the sentence means that even after a long day, they still didn’t quarrel.

It adds a contrast:

• the day was long and difficult
• nevertheless, they supported each other and did not quarrel

Very often всё равно is used to mean despite everything.

In careful spelling, it is всё равно with ё.

In many everyday texts, Russians write е instead of ё, so you may also see:

• все равно

But it is still pronounced as всё равно, not все равно in the sense of all people are equal or anything like that.

So for learners, it is best to understand this phrase as:

• всё равно = still / anyway / all the same

Both are possible in Russian, but they mean slightly different things.

• не ссорились = they were not quarrelling / they did not quarrel
• не поссорились = they did not have a quarrel / did not fall out

The difference is aspect:

• ссориться is imperfective
• поссориться is perfective

In this sentence, не ссорились emphasizes the absence of quarrelling as a process or behavior during that time.

If you said не поссорились, it would focus more on the fact that no actual falling-out happened.

The -сь is a form of -ся, the reflexive marker.

The verb is ссориться = to quarrel.

In many Russian verbs, -ся / -сь does not always mean a literal English reflexive like wash oneself. Sometimes it is just part of the normal dictionary form of the verb.

Here ссориться is the standard verb meaning to quarrel. It often has a reciprocal sense:

• они ссорились = they were quarrelling with each other

So you should learn ссориться as a whole verb.

Because и is simply joining two predicates with the same subject:

• мы поддерживали друг друга
• (мы) всё равно не ссорились

This is one sentence with one subject, so no comma is needed.

A comma would usually appear if there were separate clauses that needed clearer separation, but not in this straightforward structure.

Yes. Russian word order is flexible, and changing it changes emphasis more than basic meaning.

The version here:

• После длинного дня мы поддерживали друг друга и всё равно не ссорились.

sounds natural and balanced.

You could also hear variations like:

• Мы после длинного дня поддерживали друг друга и всё равно не ссорились.
• После длинного дня мы всё равно не ссорились и поддерживали друг друга.

These alternatives are possible, but the original order is very natural because it:

1. sets the time/background first
2. gives the first action
3. ends with the contrastive idea всё равно не ссорились

Russian has no articles.

So после длинного дня can mean:

• after a long day
• after the long day

The exact meaning depends on context.

English needs articles, but Russian usually leaves that information to context, word order, and common sense.