Eu perdi um brinco no carro, mas encontrei o outro dentro da bolsa.

Yes. Eu can be omitted here.

Portuguese often drops subject pronouns when the verb form already makes the subject clear. So:

• Eu perdi um brinco...
• Perdi um brinco...

Both mean I lost an earring...

Including Eu can add:

• emphasis
• contrast
• clarity in certain contexts

In everyday Brazilian Portuguese, dropping Eu is very common.

Both are in the pretérito perfeito (simple past / preterite).

• perdi = I lost
• encontrei = I found

This tense is used for completed actions in the past. That fits this sentence because both actions are seen as finished events:

• first, the speaker lost an earring
• then, the speaker found the other one

The infinitives are:

• perder = to lose
• encontrar = to find

This is because the speaker is introducing one item first, and then referring to the remaining one.

• um brinco = an earring
• o outro = the other one

This strongly suggests a pair of earrings:

• one earring was lost
• the other earring was found

Using o outro makes sense because once one item from the pair has been mentioned, the second one is now specific and identifiable.

Because brinco is a masculine noun in Portuguese.

So anything referring back to brinco must also be masculine:

• um brinco
• o outro

If the noun were feminine, then you would use:

• a outra

This is grammatical agreement: articles and adjectives must match the noun’s gender and number.

In this sentence, yes, brinco means earring.

But learners often notice that brinco can also be a verb form:

• eu brinco = I play / I joke

So brinco can mean different things depending on context:

• noun: an earring
• verb: I play / I joke

Here, because it comes after um, it is clearly a noun:

• um brinco = an earring

Because no is the contraction of:

• em + o = no

So:

• no carro = in the car

This kind of contraction is required in normal Portuguese.

Other common examples:

• na bolsa = em + a
• do carro = de + o
• da bolsa = de + a

So em o carro would sound unnatural in standard Portuguese.

Both can work, but dentro da bolsa is more explicit.

• na bolsa = in the bag
• dentro da bolsa = inside the bag

Dentro de emphasizes that something is physically inside something else. It can sound a little clearer or more vivid.

So:

• encontrei o outro na bolsa = natural
• encontrei o outro dentro da bolsa = also natural, with extra emphasis on inside

Because da is the contraction of:

• de + a = da

In dentro da bolsa, the full structure is:

• dentro de a bolsa → dentro da bolsa

This is a normal contraction in Portuguese.

So:

• dentro da bolsa = inside the bag

It can mean several related things depending on context.

In Brazilian Portuguese, bolsa often means:

• purse
• handbag
• bag

In this sentence, dentro da bolsa most likely means inside the purse/bag.

The exact English word depends on the situation, but the Portuguese is very natural.

Portuguese often leaves possession implied when the context makes it obvious.

So dentro da bolsa can naturally mean:

• inside the bag
• inside my bag

If the speaker wanted to be explicit, they could say:

• dentro da minha bolsa

But in everyday speech, Portuguese often uses the definite article where English would prefer a possessive.

This is very common in Portuguese.

Yes, this is the most natural word order.

• mas encontrei o outro = but I found the other one

Portuguese usually prefers:

• conjunction + verb + object

Since the subject eu is omitted, the verb comes first naturally.

You could rearrange the sentence in special contexts for emphasis, but this version is the normal, neutral order.

Because mas means but, and it connects two contrasting clauses:

• Eu perdi um brinco no carro
• mas encontrei o outro dentro da bolsa

Using a comma before mas is standard punctuation in Portuguese, just as it often is before but in English.

Both refer to location, but they are built differently.

• no carro = in the car
• dentro da bolsa = inside the bag

No carro uses the preposition em with the article:

• em + o = no

Dentro da bolsa uses the expression dentro de:

• inside of

So the sentence mixes:

• a simple location phrase: no carro
• a more specific interior-location phrase: dentro da bolsa

That is perfectly natural.

Yes. Perdi um brinco no carro most naturally means I lost an earring in the car, but that does not guarantee the earring is still there.

It usually means the loss happened in that location or was noticed there. Context decides whether:

• it was dropped there
• it disappeared while the speaker was in the car
• the speaker thinks that is where it was lost

So the phrase gives the likely location of the loss, not necessarily the current location of the earring.