Learn Polish: Czy ten bilet jest nasz?

In Polish, possessive words like nasz (our/ours) change their ending based on the gender of the noun they describe. bilet (ticket) is a masculine noun, so we use the basic masculine form nasz. If it were a feminine noun like woda (water), it would be nasza.

Does nasz mean 'our' or 'ours'?

It means both! Unlike English, Polish doesn't use a different word when the possessive stands alone. nasz bilet means 'our ticket', and bilet jest nasz means 'the ticket is ours'.

Why does the sentence start with czy?

czy is a question word used to start yes/no questions in Polish. While English swaps the word order to ask a question ('This is...' becomes 'Is this...'), Polish often keeps the normal sentence order (ten bilet jest nasz) and simply puts czy at the very beginning to make it a question.

Why do we use ten for 'this' instead of to?

Because bilet is a masculine noun. ten is the masculine word for 'this'. You might remember to from sentences like to jest bilet (this is a ticket), where to acts as a general pointing word. But when you attach 'this' directly to a specific noun to say 'this ticket', the word for 'this' has to match the noun's gender.