Library student worker, to an exiting researcher: "See you tomorrow."
Female Researcher working on a book: "No you won’t. I have to visit another library."
Librarian: "You’re cheating on us?"
Female Researcher working on a book: "Sorry, but as much as I like this library, there’s not that many prostitutes here."
Explanation, the researcher is working on book about prostitution. Or, she's "working" on a "book" about prostitution"."