Learn Polish: Czy te sektory są już otwarte? - Are these sectors already open?

The word sektory (sectors) is plural, but it doesn't refer to male people. In Polish, plural words are split into two groups: masculine personal (groups containing at least one man) and non-masculine personal (everything else, including objects, animals, and groups of only women). Because a sector is an inanimate object, we use the non-masculine personal pronoun te. The word ci is only used for masculine personal nouns.

Why does the noun sektory end in -y?

The singular form is sektor. It is a masculine inanimate noun, meaning it is grammatically masculine but not a living thing. To make regular masculine inanimate nouns plural in the Nominative case, we simply add -y to the end.

Why is the word for "open" spelled otwarte here instead of otwarty?

otwarte is an adjective describing sektory. Because sektory belongs to the non-masculine personal group in the plural, the adjective must take the matching plural ending, which is usually -e. The singular form is otwarty, but here we need the plural otwarte.

Does już mean "already" or "yet" here?