Questions & Answers about O juiz ouviu a testemunha.
Ouviu is the 3rd-person singular preterite form of ouvir (to hear).
It matches o juiz (the judge), so it means he/she heard in a completed past action.
A quick comparison:
- ouve = he/she hears
- ouvia = he/she was hearing / used to hear
- ouviu = he/she heard
In this sentence, it refers to a single completed event in the past.
They are definite articles, equivalent to the in English.
- o juiz = the judge
- a testemunha = the witness
In Portuguese, articles change for grammatical gender and number:
- o = masculine singular
- a = feminine singular
- os = masculine plural
- as = feminine plural
So o agrees with juiz, and a agrees with testemunha.