Пламя так и не стало большим, потому что мама быстро всё выключила.

Так и не is a very common Russian pattern meaning something like:

• never ended up
• didn't after all
• failed to

It often implies that a result was possible or expected, but it never happened.

So Пламя так и не стало большим means not just the flame did not become big, but more specifically the flame never did get big.

Yes, that is grammatically correct.

But the nuance changes:

• не стало большим = did not become big
• так и не стало большим = never ended up becoming big, with a stronger sense that this result was expected or could easily have happened

So так и adds emphasis and makes the sentence sound more idiomatic and expressive.

In the past tense, Russian verbs agree with the subject in gender and number.

Here the subject is пламя, and пламя is neuter singular, so the verb is стало.

Compare:

• огонь стал = the fire became
• пламя стало = the flame became
• мама стала = mom became
• дети стали = the children became

The same thing happens later in the sentence:

• мама выключила because мама is feminine singular

Because after стать meaning to become, Russian normally uses the instrumental case for the thing someone or something becomes.

So:

• стать большим = to become big
• стать учителем = to become a teacher
• стать известным = to become famous

That is why the adjective is большим, not большое.

Also, although пламя is neuter, the instrumental singular form of many masculine and neuter adjectives is the same:

• masculine: большим
• neuter: большим

Both verbs focus on results.

• стало from стать focuses on the result became
• выключила from выключить focuses on the completed action switched off

In this sentence:

• не стало большим = the result of becoming big never happened
• быстро всё выключила = she quickly switched everything off, successfully and completely

If you used imperfective forms, the meaning would shift more toward process, repetition, or background description.

For example:

• не становилось большим = was not becoming big / never used to get big
• выключала = was switching off / used to switch off

Here всё means everything.

It is the pronoun всё, not все.

• всё = everything
• все = everyone / all people / all things in the plural

In many Russian texts, ё is often written as е, but learners should know the real form here is всё.

In this sentence, всё is the direct object of выключила:

• мама быстро всё выключила = mom quickly switched everything off

Yes, выключить can work here, but it gives a specific nuance.

Выключить literally means to switch off or turn off. So the sentence suggests that the mother turned off whatever was causing or feeding the flame, for example:

• the stove
• the gas
• the electricity
• some appliance

If the focus were directly on extinguishing the flame itself, потушить would be more literal:

• мама быстро потушила пламя = mom quickly put out the flame

So:

• выключила = turned off the source
• потушила = put out the fire/flame itself

Мама is the normal everyday word for mom or mum in family speech and simple narration.

Мать is more formal, more neutral in an official sense, or sometimes harsher depending on context.

So in a sentence like this, мама sounds natural and ordinary.

Compare:

• мама пришла = mom came
• мать пришла = mother came

The second one is not wrong, but it sounds less warm and less conversational.

Because потому что introduces a subordinate clause meaning because.

Russian normally separates a subordinate clause from the main clause with a comma.

So the structure is:

• main clause: Пламя так и не стало большим
• subordinate clause: потому что мама быстро всё выключила

That is why the comma is required.

No. Russian word order is flexible, and changing it usually changes focus or emphasis, not the basic meaning.

This version is natural and clear:

• мама быстро всё выключила

Other possible orders include:

• мама всё быстро выключила
• быстро мама всё выключила
• всё мама быстро выключила

These do not all sound equally neutral. They shift attention onto different parts of the sentence.

So a good rule is:

• the meaning stays mostly the same
• the emphasis changes

Пламя is a neuter noun, and it belongs to a special group of Russian nouns ending in -мя.

Other common nouns in this group are:

• время = time
• имя = name
• знамя = banner

These nouns have some special case forms. For example:

• nominative: пламя
• genitive: пламени
• instrumental: пламенем

In your sentence, пламя is the subject, so it is in the nominative singular.

That is the most common and neutral order when giving a reason:

• statement first
• reason second

So:

• Пламя так и не стало большим, потому что мама быстро всё выключила.

You can sometimes rearrange Russian clauses for style or emphasis, but this order is the most straightforward and natural for everyday usage.