What is the difference between 'Dziewczynka czyta nową książkę' and 'Dziewczynka czytająca nową książkę' ( I have just finished the participles and gerunds section, so am curious)
The first one is a simple declarative sentence. "The girl is reading a new book".
The latter is just a long noun phrase. "The girl reading a new book..." - it needs something more to create a sentence.