This is the 143rd most frequent Polish word.
nadal
"Still" or "yet."
The word 'nadal' here means 'still' in English and indicates the continuation of an ongoing action.
Nadal pracuję nad tym projektem.
I am still working on this project.
In this sentence, 'nadal' emphasizes the ongoing state of difficulty in understanding the book over time.
Nadal nie mogę zrozumieć tej książki.
I still can't understand this book.
'Nadal' here is used to inquire whether a certain condition (living in Warsaw) persists over time.