Breakdown of Czy oni jadą na wieś na urlop?
czy
[question particle]
oni
they (masculine personal)
na
on, at / to (motion toward) / for (a meal) / for (waiting for)
jechać
to travel
Questions & Answers about Czy oni jadą na wieś na urlop?
Why is the word na used twice in this sentence?
The preposition na is very versatile! The first one, na wieś, shows the destination ("to the countryside"). The second one, na urlop, shows the purpose or event they are going for ("for a vacation"). Both of these uses require the Accusative case.
If na takes the Accusative case here, why didn't the endings of wieś and urlop change?
They actually are in the Accusative case, but their forms just happen to look exactly like their basic dictionary forms! Urlop is a masculine inanimate noun, and wieś is a feminine noun that ends in a consonant. Both of these specific noun types keep their basic dictionary form in the Accusative case.
Why does the sentence use jadą for "traveling"? Could I use idą?
You have to use jadą (from the verb jechać) because they are using some kind of vehicle to get to the countryside. Idą (from iść) specifically means going on foot. In Polish, you must always choose your verb of motion based on whether you are walking or riding.
Can oni refer to any group of people?
Oni is specifically used for groups that include at least one male. If the group was made up entirely of women, children, or animals, you would use the other Polish word for "they", which is one.