Se ele tivesse esquecido o uniforme de novo, teria voltado para casa imediatamente.

Because this is a counterfactual conditional: it talks about something that did not actually happen in the past.

In Portuguese, this pattern is very common:

• Se + pluperfect subjunctive, ... conditional perfect

So here:

• Se ele tivesse esquecido... = If he had forgotten...
• ...teria voltado... = ...he would have gone back...

This structure shows an unreal past situation: he did not forget the uniform, and therefore he did not go back home.

Tivesse esquecido is the pluperfect subjunctive.

It is made with:

• the subjunctive form of ter: tivesse
• the past participle: esquecido

So:

• ter esquecido = to have forgotten
• tivesse esquecido = had forgotten, in a subjunctive/conditional context

This tense is very often used after se when talking about unreal past conditions.

Teria voltado is the conditional perfect.

It is formed with:

• teria = conditional of ter
• voltado = past participle of voltar

Together, it means would have gone back or would have returned.

This part gives the result of the unreal condition:

• Se ele tivesse esquecido... = If he had forgotten...
• ...teria voltado... = ...he would have gone back...

Yes, very closely.

The correspondence is:

• Se ele tivesse esquecido = If he had forgotten
• teria voltado = would have gone back

So this is one of the cases where Portuguese and English match very well in meaning and structure.

Yes:

• Se = if
• ele = he
• tivesse esquecido = had forgotten
• o uniforme = the uniform
• de novo = again
• teria voltado = would have gone back / would have returned
• para casa = home
• imediatamente = immediately

So the sentence literally maps very closely to English.

Yes, de novo means again.

In Brazilian Portuguese, de novo is extremely common in everyday speech. It often sounds more natural and conversational than novamente, although both can mean again.

So:

• de novo = again
• novamente = again, again once more, sometimes a bit more formal or neutral

In this sentence, de novo suggests he may have forgotten the uniform before, so there is a sense of repetition.

In this sentence, the difference is mostly one of style and tone, not core meaning.

• de novo sounds very natural and common in Brazilian Portuguese
• novamente can sound a little more formal, careful, or written

So:

• Se ele tivesse esquecido o uniforme de novo...
• Se ele tivesse esquecido o uniforme novamente...

Both are correct. The first usually sounds more everyday and conversational.

Because in Portuguese, casa can mean home, and when it means home in a general sense, it usually appears without an article.

So:

• voltar para casa = to go back home / to return home

But if you are talking about a specific house/building, then you may use an article:

• voltar para a casa da avó = to go back to the grandmother’s house

In your sentence, para casa means simply home, not a specific house being identified.

Because voltar means to return / to go back, while ir means simply to go.

Here the idea is that if he had forgotten the uniform, he would have had to go back home from wherever he was. So voltar is the natural choice.

Compare:

• ir para casa = to go home
• voltar para casa = to go back home / return home

The sentence implies he had already left home and would have needed to return.

Yes. Portuguese often drops subject pronouns when the meaning is clear from the verb.

So you could also say:

• Se tivesse esquecido o uniforme de novo, teria voltado para casa imediatamente.

This is natural if context already makes it clear who the person is.

However, keeping ele can add clarity or emphasis, especially if you are contrasting him with someone else.

Yes. Portuguese allows some flexibility.

For example, you can invert the clauses:

• Teria voltado para casa imediatamente se ele tivesse esquecido o uniforme de novo.

This still means the same thing.

You can also move imediatamente slightly:

• Se ele tivesse esquecido o uniforme de novo, ele teria voltado imediatamente para casa.
• Se ele tivesse esquecido o uniforme de novo, teria imediatamente voltado para casa.

Some versions sound more natural than others, but the basic meaning stays the same.

It modifies the action teria voltado and means immediately.

Putting it at the end is very natural in Portuguese:

• teria voltado para casa imediatamente

It can sometimes move around, but the end position is simple and common. It keeps the sentence flowing naturally.

Yes. That is one of the key meanings of this structure.

Because it uses:

• se + tivesse esquecido
• teria voltado

the sentence strongly implies:

• he did not forget the uniform
• he did not go back home

It is describing an imagined past alternative, not a real event.

Not with exactly the same meaning.

• Se ele tivesse esquecido... refers to an unreal situation in the past
• Se ele esquecesse... usually refers to a hypothetical situation, often more general or less anchored to a completed past event

Compare:

• Se ele tivesse esquecido o uniforme, teria voltado para casa.
  = If he had forgotten the uniform, he would have gone back home.

• Se ele esquecesse o uniforme, voltaria para casa.
  = If he forgot / were to forget the uniform, he would go back home.

The second one sounds more like a hypothetical rule or repeated possibility, not a specific unreal past event.

It is part of the verb.

In tivesse esquecido, esquecido is the past participle of esquecer, and together with tivesse it forms a compound verb tense.

So here it does not function as an adjective. It is part of the verbal expression meaning had forgotten.

Yes, it sounds natural and correct.

The combination of:

• Se ele tivesse esquecido...
• teria voltado...
• de novo
• para casa imediatamente

is fully idiomatic in Brazilian Portuguese.

A Brazilian speaker might also say slight variations depending on context, but your sentence is very normal and natural.