Questions & Answers about Van egy kutya és egy macska; az utóbbi fiatal.
Because van is being used in an existential sense: there is / there are.
So:
- Van egy kutya. = There is a dog.
- Van egy kutya és egy macska. = There is a dog and a cat.
This is different from sentences like A kutya fiatal (The dog is young), where Hungarian usually does not say the present-tense is in the 3rd person.
In this kind of existential sentence, Hungarian very often uses singular van when introducing a whole situation or list as new information, even if more than one item follows.
So Van egy kutya és egy macska is natural Hungarian.
A simple way to think about it is:
- van here introduces the existence of the whole setup
- the sentence is not built exactly the same way as English there are
You will still see vannak with clearly plural subjects, for example:
- Vannak kutyák a kertben. = There are dogs in the garden.
But in this sentence, van is the normal choice.