Se ela tivesse ido ao salão ontem, teria escolhido outro penteado.

Because this is a contrary-to-fact past condition: it talks about something that did not happen in the past.

In Portuguese, when the if-clause refers to an unreal past situation, Brazilian Portuguese normally uses the pluperfect subjunctive:

• Se ela tivesse ido... = If she had gone...

This is the standard pattern for hypothetical past situations:

• Se + pluperfect subjunctive, then
• conditional perfect in the result clause

So:

• Se ela tivesse ido ao salão ontem, teria escolhido outro penteado.

Teria escolhido is the conditional perfect, used here to show the result that would have happened if the condition had been true.

So the structure is:

• Se ela tivesse ido... = the unreal condition
• ...teria escolhido... = the unreal result

This is very similar to English:

• If she had gone..., she would have chosen...

The verb form is built with:

• teria
  • past participle
• teria escolhido
• teria feito
• teria visto

Tivesse ido is made of:

• tivesse = imperfect/pluperfect subjunctive form of ter
• ido = past participle of ir

Together, ter + past participle creates a compound past form.

Here:

• ter ido = to have gone
• tivesse ido = had gone in a subjunctive environment

A few similar examples:

• Se eu tivesse visto = If I had seen
• Se nós tivéssemos chegado = If we had arrived
• Se eles tivessem estudado = If they had studied

Because after ter, Portuguese uses the past participle of the main verb.

For ir, the past participle is ido.

So:

• ela foi = she went
• ela tinha ido = she had gone
• ela tivesse ido = if she had gone

You cannot say:

• se ela tivesse foi ❌

It must be:

• se ela tivesse ido ✅

Here, se means if and introduces a conditional clause.

Portuguese se can have other meanings in other contexts, but in this sentence it is simply the conjunction if:

• Se ela tivesse ido... = If she had gone...

This is one of the most common uses of se in Portuguese.

Because ir usually takes the preposition a when expressing destination in more formal or standard patterns:

• ir a algum lugar

And salão here is used with the definite article o:

• a + o = ao

So:

• ao salão = to the salon

Breakdown:

• a
  • o salão → ao salão

You will also hear Brazilians often use ir no / ir para o in speech, depending on region and context, but ir ao salão is perfectly standard and very natural.

Because adverbs of time like ontem are flexible in Portuguese. It sounds natural at the end of the clause:

• Se ela tivesse ido ao salão ontem...

But other positions are also possible, depending on emphasis:

• Se ela tivesse ido ontem ao salão...
• Se ontem ela tivesse ido ao salão... (more marked)

The version in the sentence is the most neutral and natural.

Both are possible, but outro penteado is the more direct and common way to say another/different hairstyle.

• outro penteado = another hairstyle / a different hairstyle
• um outro penteado can also exist, but often sounds slightly more emphatic or stylistically heavier

In most everyday cases, Portuguese prefers simply:

• outro livro
• outra ideia
• outro penteado

It can mean either, depending on context.

In this sentence, it most naturally means:

• a different hairstyle or
• another hairstyle

Since the sentence is hypothetical, the idea is that she would have chosen a hairstyle different from the one she actually ended up with or different from the expected one.

Portuguese outro often covers both English ideas:

• another
• other/different

Not in this sentence if you want to keep the same standard grammar and meaning.

For an unreal past condition, the normal pattern is:

• Se ela tivesse ido..., teria escolhido...

Using ia escolher would not fit as well here, because the sentence is specifically about a past hypothetical result. The conditional perfect teria escolhido clearly marks that.

Compare:

• teria escolhido = would have chosen
• ia escolher = was going to choose / would choose (in some contexts), but not the best match here

So the original version is the correct and natural one for this structure.

In standard grammar, no. For this kind of unreal past condition, Portuguese uses the subjunctive, not the indicative.

So:

• Se ela tivesse ido... ✅
• Se ela tinha ido... ❌ for this meaning

Tinha ido is the pluperfect indicative and does not work properly here in standard Portuguese when expressing a hypothetical contrary-to-fact condition.

Yes. This is the standard way to express a third conditional type of idea in Portuguese: an unreal condition in the past and its unreal result.

The pattern is very important:

• Se + tivesse/tivessemos/tivessem + participle
• teria/teríamos/teriam + participle

Examples:

• Se eu tivesse estudado, teria passado.
• Se eles tivessem chegado cedo, teriam visto tudo.
• Se nós tivéssemos saído antes, teríamos evitado o trânsito.

So the sentence is a very useful model for learners.

The subject is ela in both clauses.

• Se ela tivesse ido ao salão ontem
  Subject: ela

• teria escolhido outro penteado
  The subject is still ela, but Portuguese often omits repeated subject pronouns when they are already clear.

So in full, you could think of it as:

• Se ela tivesse ido ao salão ontem, ela teria escolhido outro penteado.

The second ela is omitted because it is unnecessary.