Prošle zime i mama i ja imale smo gripu, pa smo obje bile na bolovanju.

Because Croatian often uses the genitive to express time when something happened, especially with seasons and parts of the year.

So:

• zima = winter
• prošla zima = last winter
• prošle zime = last winter / during last winter

This is a very common time expression, similar to:

• ovog ljeta = this summer
• prošle godine = last year
• idućeg tjedna = next week

So Prošle zime means last winter or during last winter.

This is a common Croatian pattern meaning both ... and ...

So:

• i mama i ja = both mom and I
• literally: and mom and I

The repeated i is normal here. You can compare:

• i brat i sestra = both the brother and the sister
• i ti i ja = both you and I

It is not awkward in Croatian the way a literal English translation would sound.

Because the past participle agrees with the gender and number of the subject.

Here the subject is:

• mama
• ja

If the speaker is female, then both people are female, so Croatian uses the feminine plural:

• imale smo
• bile smo

If the speaker were male, Croatian would normally use the masculine plural:

• i mama i ja imali smo gripu
• pa smo oboje bili na bolovanju

So the sentence tells you that the speaker is female.

Because once ja is part of the subject, Croatian uses first person plural.

So:

• ja + netko drugi = we
• therefore: smo

That is why you get:

• i mama i ja imale smo
• not a third-person plural form like su

The same thing happens in English:

• Mom and I were sick
• not Mom and I was or some special third-person form

Because gripu is the accusative singular of gripa.

The verb imati (to have) takes a direct object in the accusative:

• imati gripu = to have the flu
• imati temperaturu = to have a fever
• imati prehladu = to have a cold

So:

• gripa = nominative
• gripu = accusative

That is why the sentence says imale smo gripu.

Here pa means something like:

• so
• and so
• and then
• therefore

It connects the two ideas:

1. We had the flu.
2. As a result, we were on sick leave.

So pa shows a natural consequence or continuation.

Obje means both, and it is the feminine form.

It refers to the two female people already mentioned: mama and ja.

Compare:

• obje = both, for feminine plural
• oba = both, for masculine/neuter in some uses

In this sentence, obje adds emphasis: not just we, but both of us.

So:

• smo obje bile na bolovanju = both of us were on sick leave

Bile is the feminine plural past participle of biti (to be), matching the two female subjects.

The phrase na bolovanju is a fixed expression meaning on sick leave.

So:

• biti na bolovanju = to be on sick leave

This is very idiomatic Croatian. Literally, na often corresponds to English on in expressions of status or activity:

• na odmoru = on vacation
• na poslu = at work
• na bolovanju = on sick leave

So bile na bolovanju is exactly the natural way to say this.

Because Croatian word order is fairly flexible, especially in past-tense phrases.

Both of these are normal:

• imale smo
• smo ... bile

The auxiliary smo is a clitic, so it tends to appear early in the clause, but Croatian still allows different natural patterns depending on rhythm, emphasis, and what comes before it.

In this sentence:

• imale smo gripu sounds natural after the subject
• pa smo obje bile... also sounds natural, with smo coming early after pa

So this is not something strange or incorrect—just normal Croatian word order.

Because pa here connects two full clauses:

• i mama i ja imale smo gripu
• pa smo obje bile na bolovanju

In Croatian, when two clauses are joined like this, a comma is commonly used before pa, especially when the second clause expresses a result or continuation.

So the comma helps separate the two parts of the sentence clearly.