Na reunião de hoje, o resto do relatório ficou por comentar.

Na is the contraction of em + a.

• em = in / at
• a = the feminine singular definite article the

So na reunião means in the meeting or at the meeting.

It is feminine because reunião is a feminine noun: a reunião.

Because hoje is an adverb, not a noun.

• de hoje = of today / today’s
• da would be de + a, and that only works before a feminine noun with an article

So a reunião de hoje means today’s meeting.

This is a very common Portuguese structure:

• a aula de hoje = today’s class
• o jornal de hoje = today’s newspaper
• a conversa de hoje = today’s conversation

Literally, it means the rest of the report.

Breakdown:

• o resto = the rest / the remainder
• do relatório = de + o relatório = of the report

So:

• o resto do relatório = the remaining part of the report

This is a normal noun + de + noun structure in Portuguese.

Do is the contraction of de + o.

• de = of
• o relatório = the report

So:

• de o relatório becomes do relatório

This kind of contraction is extremely common in Portuguese:

• da = de + a
• dos = de + os
• das = de + as

Because the grammatical subject is o resto, and resto is singular.

Even though the meaning refers to a larger part of the report, the head noun is still singular:

• o resto do relatório ficou... = singular
• as partes restantes do relatório ficaram... = plural

This is similar to English in a sentence like the rest of the report was left..., where rest is treated as singular.

This is a very common Portuguese pattern:

ficar por + infinitive

It means something like:

• to remain to be done
• to be left undone
• to end up not being done

So ficou por comentar means:

• was left uncommented
• remained to be discussed
• did not get discussed/commented on

In this sentence, the idea is that during today’s meeting, part of the report was not discussed.

Because ficar por + infinitive is a fixed and very common structure meaning to remain undone.

So:

• ficou por comentar = it was left undiscussed / it remained to be discussed

By contrast, ficar para + infinitive usually means something more like to be left for later or to be postponed for something.

Compare:

• Ficou por comentar.
  = It did not get discussed.

• Ficou para comentar amanhã.
  = It was left to discuss tomorrow.

That is an important distinction.

Not only.

In English, to comment can sound narrow, but in Portuguese comentar often has a broader sense, especially in formal or workplace contexts. It can mean:

• to comment on
• to discuss
• to go over
• to mention and examine briefly

So in a meeting context, comentar o relatório can mean to discuss the report or to go over the report, not just to make a casual remark about it.

Because ficou gives a strong sense of the resulting state after the meeting.

• ficou por comentar = it ended up left undiscussed
• estava por comentar = it was still to be discussed / it was pending discussion
• foi por comentar is not idiomatic here

So ficou works well because the sentence is looking back at the meeting and stating the outcome: after the meeting, the rest of the report was still not discussed.

Also, ficou is the preterite of ficar, so it presents that outcome as a completed fact.

Yes, in meaning, but not a standard passive with ser + past participle.

Ficou por comentar is more of a resultative or semi-passive structure. It focuses on the state something ended up in, without saying who failed to do the action.

So instead of saying:

• ninguém comentou o resto do relatório = nobody commented on the rest of the report

Portuguese uses:

• o resto do relatório ficou por comentar = the rest of the report was left undiscussed

This sounds more neutral and impersonal, which is very common in formal speech and writing.

Because Na reunião de hoje is an introductory time/location phrase placed at the beginning of the sentence.

The comma separates that introductory element from the main clause:

• Na reunião de hoje, = In today’s meeting,
• o resto do relatório ficou por comentar.

The comma is natural and standard here, especially because the opening phrase is fairly long. You may sometimes see short introductory phrases without a comma, but in this sentence the comma is the normal choice.

Yes. A few natural alternatives are:

• Na reunião de hoje, ficou por comentar o resto do relatório.
• Na reunião de hoje, o resto do relatório não chegou a ser comentado.
• Na reunião de hoje, não se comentou o resto do relatório.

They are all natural, but the original sentence is very good because it sounds neutral, concise, and formal. It is the kind of phrasing you might hear in a meeting summary or read in a report.