Ja i moja sestra smo juče bile zajedno u parku.

to be

Breakdown of Ja i moja sestra smo juče bile zajedno u parku.

• ja: I
• u: in
• i: and

Questions & Answers about Ja i moja sestra smo juče bile zajedno u parku.

Why is the verb form bile used here instead of bili?

Because the speakers are two females: ja refers to a female speaker, and moja sestra is also female.

In Serbian past tense, the l-participle agrees in gender and number:

• bio / bila = singular masculine / feminine
• bili / bile = plural masculine or mixed / plural feminine

So:

• Ja i moj brat smo bili... = I and my brother were...
• Ja i moja sestra smo bile... = I and my sister were...

If even one male is included in the group, Serbian normally uses masculine plural: bili.

Why is it smo bile and not just one verb form?

Serbian past tense is made with two parts:

1. a present-tense form of biti (sam, si, je, smo, ste, su)
2. the l-participle (bio, bila, bili, bile, etc.)

So smo bile literally consists of:

• smo = we are / auxiliary for we
• bile = been / were (feminine plural form)

Together they mean we were.

This is the normal way to form the past tense in Serbian.

Why does the sentence start with Ja i moja sestra? Could be omitted?