Questions & Answers about Mój brat i jego nowa partnerka przyszli na przyjęcie.
Why is the verb przyszli used when one of the people is female (partnerka)?
In Polish, if a mixed group contains at least one male person (in this case, brat), the whole group is treated grammatically as masculine personal (virile). This means the past tense verb must take the masculine personal plural ending -li (przyszli) rather than the non-masculine -ły (przyszły).
Why is it jego nowa partnerka and not a feminine form of 'his'?
Jego (his) tells us who the partner belongs to—the brother. Because it is a fixed possessive pronoun (literally the genitive form of on, meaning 'of him'), it does not change to match the feminine gender of partnerka. Only the adjective nowa must agree with the feminine noun.
Why does the sentence use na przyjęcie instead of do przyjęcia for going 'to' the reception?
We use the preposition na (followed by the accusative case) because a reception (przyjęcie) is an event or gathering, not an enclosed physical structure. You go do a building (like a restaurant or house), but na an event (like a party, concert, or meeting).
Does partnerka just mean a business partner, or is it used for romantic relationships too?