O dono pagou a conta.

Because Portuguese definite articles change according to the gender and number of the noun.

• o = masculine singular
• a = feminine singular
• os = masculine plural
• as = feminine plural

So:

• o dono = masculine singular
• a conta = feminine singular

English just uses the for all of these, but Portuguese has to match the noun.

Dono usually means owner, holder, or the person who possesses something.

It is a common everyday word. Depending on context, it can mean:

• the owner of a shop
• the owner of a house
• the person in charge of something

The feminine form is dona.

Examples:

• O dono da loja = the owner of the shop
• A dona da casa = the female owner of the house / the lady of the house

Pagou is the 3rd person singular preterite of the verb pagar.

That means it corresponds to:

• he paid
• she paid
• it paid
• you paid (formal você)

The preterite is used for a completed action in the past.

So pagou tells us that the paying happened and is finished.

Compare:

• pagou = paid, did pay
• pagava = was paying / used to pay

Because the subject is already expressed as O dono.

Portuguese does not need an extra subject pronoun when the subject is clearly stated.

So:

• O dono pagou a conta. = The owner paid the bill.

You would only use a pronoun like ele if you wanted to replace the noun or emphasize it:

• Ele pagou a conta. = He paid the bill.

In this sentence, O dono already does that job.

Because in Portuguese, pagar usually takes a direct object when you say what was paid.

So you say:

• pagar a conta
• pagar o jantar
• pagar a multa

This is different from some English patterns where learners may expect an extra word.

However, when you say who was paid, Portuguese often uses a:

• pagou ao empregado = paid the employee
• pagou ao médico = paid the doctor

So:

• pagar a conta = pay the bill
• pagar ao empregado = pay the employee

No. Conta can mean different things depending on context.

Common meanings include:

• bill / check in a restaurant or café
• account in banking or online services
• sometimes calculation or sum, depending on the context

In a sentence like O dono pagou a conta, the most natural meaning is the bill.

Examples:

• conta do restaurante = restaurant bill
• conta bancária = bank account

Yes, but O dono pagou a conta is the most neutral and natural word order.

This is the standard pattern:

subject + verb + object

• O dono = subject
• pagou = verb
• a conta = object

Other orders are possible in Portuguese, but they usually sound:

• more literary,
• more marked,
• or more dependent on context and emphasis.

For a learner, the safest choice is to keep: O dono pagou a conta.

You would change the article and noun to the feminine form:

• A dona pagou a conta.

Here:

• o dono → masculine
• a dona → feminine

If it were plural:

• Os donos pagaram a conta. = The owners paid the bill.
• As donas pagaram a conta. = The female owners paid the bill.

Notice that the verb also changes in the plural:

• pagou → singular
• pagaram → plural

In normal Portuguese, that would sound unnatural and incomplete.

Portuguese uses articles much more often than English does, especially with ordinary countable nouns like dono and conta.

So the natural form is:

• O dono pagou a conta.

Leaving out the articles would usually only happen in very special styles, headlines, notes, or non-native speech.

In European Portuguese, pagou is pronounced roughly like puh-GOH, with the stress on the last syllable.

A few useful points:

• the g is a hard g, like in go
• the ending -ou in modern European Portuguese is often pronounced close to a single ô sound, not like English ow
• the stress is on gou

So:

• pagou ≈ puh-GOH

A rough pronunciation of the full sentence is:

u DO-noh puh-GOH uh KON-tuh

That is only an approximation for English speakers, but it helps as a starting point.