Questions & Answers about Eu comprei três livros ontem.
Yes. In Portuguese, the subject pronoun is often dropped because the verb ending already shows who the subject is.
- Eu comprei três livros ontem. = I bought three books yesterday.
- Comprei três livros ontem. = Same meaning; still clearly I bought them.
You usually keep eu:
- for emphasis (Eu comprei, not someone else), or
- in very short contexts where it might be ambiguous.
Comprei is the 1st person singular (eu) of the pretérito perfeito (simple past) of comprar.
Conjugation of comprar in the pretérito perfeito:
- eu comprei – I bought
- você/ele/ela comprou – you/he/she bought
- nós compramos – we bought
- vocês/eles/elas compraram – you (pl.)/they bought
So comprei means “I bought”.
Comprar is the infinitive: to buy.
Because comprei matches eu (I), and comprou matches você/ele/ela (you/he/she).
- Eu comprei três livros. – I bought three books.
- Você comprou três livros. – You bought three books.
- Ele comprou três livros. – He bought three books.
In Portuguese, the verb ending changes with the subject. Using comprou with eu would be incorrect.
Both are past tenses, but they express different ideas:
Comprei (pretérito perfeito): a completed action at a specific time.
- Eu comprei três livros ontem. – I bought three books yesterday (finished event).
Comprava (pretérito imperfeito): a habitual, ongoing, or background past action.
- Quando eu era criança, eu comprava muitos livros. – When I was a child, I used to buy many books.
- Eu comprava livros enquanto esperava você. – I was buying books while I was waiting for you.
In your sentence, it’s a single completed purchase, so comprei is correct.
Yes, you can. All of these are grammatically correct and natural:
- Eu comprei três livros ontem.
- Ontem eu comprei três livros.
- Eu ontem comprei três livros. (less common in speech, but possible)
The most usual ones in everyday speech are:
- Eu comprei três livros ontem.
- Ontem eu comprei três livros.
Moving ontem to the beginning often adds a bit more emphasis on yesterday.
No. The noun must agree in number with the numeral.
- três livros = correct (three books – plural)
- três livro = incorrect
In general, with numbers greater than one, the noun is plural:
- dois carros – two cars
- quatro casas – four houses
- dez amigos – ten friends
You can add an article, but it changes the meaning slightly:
- Eu comprei três livros ontem. – I bought three (unspecified) books yesterday.
- Eu comprei os três livros ontem. – I bought the three books yesterday (the listener already knows which three).
So:
- No article (três livros): indefinite, new or not specifically identified books.
- With article (os três livros): definite, specific books previously mentioned or understood from context.
The accent in três (é) shows:
- Where the stress is: on the only syllable, but also
- The vowel quality: it’s a closed /e/ sound, roughly like the “e” in “say” (without the final y sound).
Without the accent, tres would be:
- either wrong spelling
- or follow different pronunciation rules.
Correct pronunciation is closer to “trehs” (one syllable, stressed).
Approximate pronunciation (Brazilian, neutral):
- Eu – like “eh-oo” gliding quickly, often almost “eu” as one sound.
- comprei – “kõm-PREI”
- om is nasal (like French on),
- ei like English “ay”.
- três – “trehs” (single syllable, closed ê, final s like English “s”).
- livros – “LEE-vrus”
- li like “lee”,
- final -os often reduced to something like “us” in casual speech.
- ontem – “Õ-tem”
- on nasal again,
- final -em often sounds like nasal “ẽĩ”, something between “eng” and “einh”.
Said smoothly:
Eu comprei três livros ontem.
No, that’s incorrect in Portuguese.
- Comprado is the past participle (“bought”), not the main past tense form.
- To say “I bought,” you must use the conjugated verb comprei, not the participle.
Correct forms:
- Eu comprei três livros ontem. – I bought three books yesterday.
- Eu tenho comprado muitos livros. – I have been buying many books (ongoing habit), different meaning.
So “Eu comprado três livros ontem” is ungrammatical.
Eu comprei corresponds most naturally to “I bought” (simple past), not to “I have bought.”
- Eu comprei três livros ontem.
= I bought three books yesterday.
(single, completed event at a specific time)
English “I have bought” usually implies a result or relevance in the present:
- “I have bought three books (so now I own them).”
Portuguese usually still uses pretérito perfeito for that:
- Eu comprei três livros. (context will convey the present relevance.)
The Portuguese present perfect (tenho comprado) has a more repetitive/ongoing meaning:
- Eu tenho comprado muitos livros. – I’ve been buying a lot of books (repeatedly, over a period).
Several word orders are possible, but these are the most natural:
- Ontem de manhã eu comprei três livros.
- Eu comprei três livros ontem de manhã.
Less common, but still acceptable:
- Ontem eu comprei três livros de manhã.
In general:
- Place broader time first (ontem = yesterday), then more specific (de manhã = in the morning),
- Keep the adverbial block together either at the beginning or end of the sentence.