Translation:My mom is writing a book on Thursday.
It must be a really short book.
So " w czwartek pisze ksiazke", but if use a month, like february, i say " w lutym pisze ksiazke", right?
If so, why do i use nominative for monday and locative (i guess) for february ? Why not locative for both ?
Why do you say on Thursday , but in February? Why not use in for both?
Btw, w czwartek is accusative.
In English we would likely say "her book" writing a book sounds strange