Praha je hlavní město České republiky. Jedná se o město ležící na řece Vltavě. — Prague is the capital of the Czech Republic. It is situated on the Vltava river.
Usage notes
The pattern of phrasing "A je B. Jedná se o C" is often semantically equivalent to "A je B. A je C", and can be rendered as "A is B. It is C". In general, the part "Jedná se o C" has an unclear subject, one that is to be sought somewhere in the sentence that precedes it.