Por causa do problema técnico, os bilhetes ficaram por imprimir.

Por causa de is a fixed expression meaning because of.

In the sentence, de combines with the masculine singular article o:

• de + o = do

So:

• por causa de o problema técnico → por causa do problema técnico

This kind of contraction is very common in Portuguese.

A few similar ones:

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

Because problema is one of the nouns that end in -a but are still masculine.

So you say:

• o problema
• um problema
• o problema técnico

This happens with several words of Greek origin, such as:

• o sistema
• o tema
• o programa

So the ending -a does not always mean the noun is feminine.

Portuguese uses definite articles much more often than English.

So where English might say:

• tickets

Portuguese often naturally says:

• os bilhetes

Here, os bilhetes refers to the specific tickets being discussed, not tickets in general.

That use of the article is very normal in Portuguese and often sounds more natural than leaving it out.

In this sentence, bilhetes means tickets.

In European Portuguese, bilhete is a very common word for things like:

• train tickets
• concert tickets
• travel tickets

Depending on context, bilhete can also mean a note or short written message, but here the meaning is clearly tickets.

A useful regional note:

• In Portugal, bilhete is the normal word.
• In Brazil, ingresso is often used for admission tickets.

Ficaram is the pretérito perfeito (simple past) of ficar, third person plural.

The verb ficar here agrees with os bilhetes, which is plural.

So:

• o bilhete ficou
• os bilhetes ficaram

In this sentence, the simple past reports what happened: the tickets ended up / were left unprinted.

Because ficar in this structure does not simply mean to stay in the literal physical sense. It often means to end up, to remain, or to be left in a certain state.

In ficar por + infinitive, the idea is:

• something remained still to be done
• something was left undone
• something did not get done

So os bilhetes ficaram por imprimir means the tickets were left unprinted / remained to be printed.

This is a very natural structure in Portuguese, especially in written or formal language.

Here, por imprimir means still to be printed or left to print.

This is the pattern:

• ficar por + infinitive

It expresses something pending or not completed.

Examples:

• ficou por fazer = it was left undone
• ficou por dizer = it remained unsaid
• ficou por resolver = it remained unresolved

So por here is not being used in the basic sense of for. It is part of the expression ficar por + infinitive.

Because after por, this structure uses the infinitive:

• por imprimir
• por fazer
• por resolver

So the sentence uses the pattern ficar por + infinitive, not a passive adjective structure.

If you wanted a different construction, you could say:

• os bilhetes não foram impressos = the tickets were not printed

That is grammatically correct too, but it is a different structure.

Compare the nuance:

• ficaram por imprimir = they were left unprinted / remained pending
• não foram impressos = they were not printed

The first one often emphasizes the idea of an unfinished task.

Yes, but the nuance changes a bit.

1. Os bilhetes ficaram por imprimir

   • very natural
   • emphasizes that printing was still pending / left undone

2. Os bilhetes ficaram sem imprimir

   • also possible
   • emphasizes the resulting state: they ended up without being printed

3. Os bilhetes não foram impressos

   • straightforward passive
   • simply states that they were not printed

So all three can work, but ficaram por imprimir is especially good when you want the sense of an unfinished task caused by the technical problem.

Because Por causa do problema técnico is an introductory phrase placed before the main clause.

The comma helps separate:

• the cause/explanation: Por causa do problema técnico
• from the main statement: os bilhetes ficaram por imprimir

This is very natural punctuation.

You could also place the cause later:

• Os bilhetes ficaram por imprimir por causa do problema técnico.

In that version, the comma is not needed.