A run-on sentence (frase corrida or, more colloquially, frase colada) happens when two or more independent clauses are jammed together without the punctuation or conjunction they need to stand apart. Portuguese tolerates longer sentences than English — a formal paragraph can run for five or six lines without feeling wrong — but there is still a clear line between a well-built long sentence and a genuinely run-on one. This page shows you where that line is, what the typical learner errors look like, and the five standard strategies for fixing them.
The two kinds of run-on
1. The comma splice (frase colada / vírgula intrusa)
A comma splice is when two independent clauses are glued together with a comma alone — no conjunction, no stronger punctuation. It's the single most common sentence-joining error in learner writing.
❌ Estava a chover muito, não saí de casa.
Comma splice — two independent clauses with only a comma between.
The two halves — estava a chover muito and não saí de casa — are each complete sentences. A comma alone is not strong enough to link them; Portuguese needs either a conjunction (por isso, portanto, e, mas) or stronger punctuation (a semicolon or a full stop).
2. The fused sentence (frase fundida)
A fused sentence is even more extreme: two independent clauses run together with no punctuation at all.
❌ Estava a chover muito não saí de casa.
Fused sentence — no punctuation at all.
✅ Estava a chover muito; não saí de casa.
It was raining a lot; I didn't go out.
This is almost always a writing error rather than a style choice — the writer's thought kept going and the punctuation never caught up.
Why Portuguese tolerates longer sentences — and where that tolerance stops
Portuguese, like other Romance languages, accepts longer sentences in formal prose than English does. A well-written Portuguese paragraph often consists of two or three long, richly subordinated sentences where the English equivalent would break into six or seven short ones.
Apesar de chover intensamente e de todos sabermos que o trânsito ia estar caótico, decidimos na mesma avançar para Lisboa, já que o espetáculo era imperdível e tínhamos comprado os bilhetes há meses.
Despite the heavy rain and despite all of us knowing that the traffic was going to be chaotic, we decided to head to Lisbon anyway, since the show was unmissable and we had bought the tickets months ago.
This 30-word sentence is long but perfectly well-formed — each clause is properly subordinated, and the subordinators (apesar de, já que, e) keep the structure transparent.
The tolerance ends the moment two independent clauses sit side by side with nothing but a comma between them. That is a run-on in any register of Portuguese.
Five strategies for fixing a run-on
Each strategy creates a different shade of meaning. Good writers don't pick mechanically — they pick the one that best captures the logical relationship between the two ideas.
Strategy 1: Full stop + new sentence
The simplest fix. Break the run-on into two separate sentences.
✅ Ele chegou atrasado. Ninguém reparou.
He arrived late. No one noticed.
This creates a staccato feel — two crisp facts, no logical glue. Use it when the two clauses are independent observations rather than cause-and-effect.
Strategy 2: Semicolon
When the two clauses are closely related but you want to keep them in one sentence, use a semicolon. This is the most formal-feeling fix and is common in essayistic and journalistic writing.
✅ Ele chegou atrasado; ninguém reparou.
He arrived late; no one noticed.
✅ O relatório é denso; leia-o com atenção.
The report is dense; read it carefully.
✅ Os preços subiram; a procura caiu.
Prices rose; demand fell.
The semicolon signals that the clauses belong together as a pair — often with a contrast or a consequence — without spelling out the connection with a word.
Strategy 3: Coordinating conjunction
Insert a coordinator — e, mas, ou, nem, pois, por isso, portanto — that names the logical relationship explicitly.
❌ Queria ir à praia, estava frio.
Comma splice with contrast.
✅ Queria ir à praia, mas estava frio.
I wanted to go to the beach, but it was cold.
❌ Perdi a carteira, tive de voltar a casa.
Comma splice with consequence.
✅ Perdi a carteira, por isso tive de voltar a casa.
I lost my wallet, so I had to go back home.
❌ Podemos jantar em casa, podemos ir ao restaurante.
Comma splice with alternative.
✅ Podemos jantar em casa ou podemos ir ao restaurante.
We can have dinner at home or we can go to the restaurant.
Strategy 4: Subordination
Turn one of the clauses into a subordinate clause. This is often the most elegant fix, because it makes the logical relationship explicit and avoids repeating subjects and pronouns.
❌ Estava cansado, fui para a cama.
Comma splice.
✅ Como estava cansado, fui para a cama.
Since I was tired, I went to bed.
❌ Tenho tempo agora, gostava de falar contigo.
Comma splice.
✅ Agora que tenho tempo, gostava de falar contigo.
Now that I have time, I'd like to talk with you.
❌ A reunião terminou, saímos todos.
Comma splice.
✅ Assim que a reunião terminou, saímos todos.
As soon as the meeting ended, we all left.
Subordinators like porque, como, quando, assim que, logo que, já que, embora, se transform what used to be a second independent clause into a dependent one — and the problem dissolves.
Strategy 5: Reduce one clause to a phrase
Sometimes a clause contains the same subject as its neighbour and can be reduced to a participial phrase, a gerund phrase, or a prepositional phrase.
❌ Voltei a casa, tomei um duche, saí outra vez.
Three clauses with comma splices.
✅ Ao chegar a casa, tomei um duche e saí outra vez.
On getting home, I showered and went out again.
❌ Pensou durante muito tempo, depois decidiu.
Comma splice with temporal sequence.
✅ Depois de pensar durante muito tempo, decidiu.
After thinking for a long time, he decided.
❌ Estava cansado, caí no sofá.
Comma splice.
✅ Cansado, caí no sofá.
Tired, I collapsed on the sofa.
Reducing a clause to an adjective, participle, or prepositional phrase tightens the sentence without losing meaning.
A closer look at typical learner errors
Here are the patterns we see most often in B1 learner writing, each with the fix that reads most naturally.
Error type 1: Translated-from-English comma splice
❌ Gosto muito de Lisboa, é uma cidade linda.
Comma splice — direct translation from English 'I love Lisbon, it's a beautiful city'.
✅ Gosto muito de Lisboa — é uma cidade linda.
I love Lisbon — it's a beautiful city.
✅ Gosto muito de Lisboa, que é uma cidade linda.
I love Lisbon, which is a beautiful city.
✅ Gosto muito de Lisboa. É uma cidade linda.
I love Lisbon. It's a beautiful city.
English writers often splice two related observations with a comma. Portuguese accepts a dash, a relative clause, or a full stop — but not a bare comma.
Error type 2: Chained actions without coordinators
❌ Acordei, tomei o pequeno-almoço, fui trabalhar, almocei na cantina.
Comma-chained actions.
✅ Acordei, tomei o pequeno-almoço, fui trabalhar e almocei na cantina.
I woke up, had breakfast, went to work, and had lunch in the canteen.
A list of actions can be comma-separated as long as the final item takes e. Without the final e, the chain reads as a run-on.
Error type 3: Connective adverb mistaken for a conjunction
Words like no entanto, contudo, além disso, por outro lado, de facto, aliás look like conjunctions but grammatically behave like adverbs. They cannot join two independent clauses with just a comma before them.
❌ O plano parecia bom, no entanto, falhou.
The middle comma is fine, but the first comma is a splice.
✅ O plano parecia bom; no entanto, falhou.
The plan seemed good; however, it failed.
✅ O plano parecia bom. No entanto, falhou.
The plan seemed good. However, it failed.
No entanto, contudo, porém, todavia, além disso need a semicolon or full stop before them — like English however. If you only put a comma, you have spliced.
Error type 4: Subject-less second clause
Learners sometimes drop the subject (correctly — Portuguese is pro-drop) and then forget that the two clauses still need a conjunction or stronger punctuation.
❌ Ela chegou cedo, começou logo a trabalhar.
Comma splice — both clauses still independent despite shared subject.
✅ Ela chegou cedo e começou logo a trabalhar.
She arrived early and started working right away.
Even when the second clause drops the pronoun, the verb começou still makes it a complete independent clause. You still need e (or a full stop, or a subordination).
Register: when longer sentences are actually fine
Formal Portuguese — essays, editorials, legal and academic writing — genuinely tolerates longer sentences than English of the same register. Three clauses linked with e, mas, pois and a subordinate clause tucked inside can all cohabit without problem, provided the punctuation and conjunctions do their job.
O autor sustenta que a reforma é urgente, pois os indicadores económicos continuam a deteriorar-se, e defende ainda que, caso não se atue depressa, o país perderá competitividade face aos parceiros europeus.
The author maintains that reform is urgent, since the economic indicators continue to deteriorate, and further argues that, should action not be taken quickly, the country will lose competitiveness against its European partners.
This is 42 words in a single sentence — and it is perfectly well-formed. Every independent clause is tied to the next by a coordinator or subordinator; every subordinate clause is properly marked by a subordinator; every parenthetical phrase is set off by commas. Length is not the issue. Missing glue is.
A step-by-step checklist
When you suspect a run-on in your own writing:
- Find the finite verbs. How many are there? A sentence can have many finite verbs, but each independent clause needs its own glue.
- Identify the independent clauses. Can each piece stand alone as a sentence? If yes, it's independent.
- Check the glue between them. Is there a coordinator (e, mas, ou, pois, portanto, por isso), a subordinator (porque, quando, embora, se), or a strong punctuation mark (semicolon, colon, full stop)? A lone comma is not enough.
- Choose a fix. Decide on the logical relationship — addition, contrast, cause, consequence, time, concession — and pick the conjunction or subordinator that names it.
- Reread aloud. If a pause wants to fall at the comma, consider a semicolon or full stop. If the pause is short, add a conjunction.
Common Mistakes
❌ O tempo está péssimo, vamos ficar em casa.
Comma splice.
✅ O tempo está péssimo, por isso vamos ficar em casa.
The weather's terrible, so we're staying home.
Two independent clauses glued with a comma. Por isso names the consequence cleanly.
❌ Ela está doente, não pode vir à festa.
Comma splice.
✅ Ela está doente, por isso não pode vir à festa.
She's sick, so she can't come to the party.
✅ Como ela está doente, não pode vir à festa.
Since she's sick, she can't come to the party.
Either coordinate with por isso or subordinate with como — both work, with slightly different rhetorical effects.
❌ Estudei muito, no entanto, o exame correu mal.
Splice before the connective adverb.
✅ Estudei muito; no entanto, o exame correu mal.
I studied a lot; however, the exam went badly.
Before no entanto, contudo, porém, todavia, além disso you need a semicolon or full stop — a bare comma is a splice.
❌ Liguei-te várias vezes ninguém atendeu.
Fused sentence — no punctuation.
✅ Liguei-te várias vezes, mas ninguém atendeu.
I called you several times, but no one answered.
The fused version runs straight from one clause to the next. Mas fills the gap.
❌ Acordei cedo, saí de casa, apanhei o comboio, cheguei ao escritório.
Chain of clauses with no final e.
✅ Acordei cedo, saí de casa, apanhei o comboio e cheguei ao escritório.
I woke up early, left home, caught the train, and arrived at the office.
Portuguese list-of-actions rhythm requires e before the final clause. Without it, the chain reads as a run-on.
❌ Ele disse que vinha, depois nunca apareceu.
Splice despite one subordinate clause.
✅ Ele disse que vinha, mas depois nunca apareceu.
He said he was coming, but then he never showed up.
The first clause contains a subordinate que vinha, but the outer clauses Ele disse (...) and (depois) nunca apareceu are still two independents. A conjunction is still required.
Key Takeaways
- A run-on joins two independent clauses without enough glue. The two kinds are the comma splice (,) and the fused sentence (no punctuation at all).
- Portuguese tolerates longer sentences than English — but only when every independent clause is properly joined.
- Five fixes: full stop, semicolon, coordinator, subordinator, or reduction of one clause to a phrase.
- Connective adverbs like no entanto, contudo, porém, além disso are not conjunctions — they take a semicolon or full stop before them, not a comma.
- Test every sentence: if each half could stand alone, you need more than a comma between them.
Related Topics
- Compound SentencesA2 — Two or more independent clauses joined by coordinating conjunctions like e, mas, ou, porém — each side could stand alone as its own sentence.
- Complex SentencesA2 — Main clauses with dependent subordinate clauses joined by que, quando, se, porque, embora, and other subordinators.
- Simple SentencesA1 — Single-clause sentences in Portuguese — the smallest complete unit of meaning, with one subject and one main verb.
- Parallel StructureB2 — Maintaining grammatical consistency in lists and comparisons — why gosto de nadar, correr e ler works but gosto de nadar, corrida e ler does not.
- Coordinating Conjunctions (E, Ou, Mas, Nem)A1 — Joining independent clauses of equal weight — the four workhorses *e*, *ou*, *mas*, and *nem*, plus the semi-coordinators *também* and *bem como*.
- Conjunctions OverviewA2 — Words that connect clauses and sentences in Portuguese — from simple *e* and *mas* to the formal *uma vez que* and *dado que*.