I have a question about the declension of czas. Please correct me if I am wrong but I think that: I don't have a lot of time = Nie mam dużo czasu and I have a lot of time = Mam dużo czasu
If the above is correct, why is czasu used in both sentences? The first sentence takes the genitive because of nie. Shouldn't the second sentence take the accusative (Mam dużo czas)?