Public libraries mean exactly that: they are here for the public in general. Not just for you. Remember that next time you go to the library. We are not Barnes & Noble where you can sip your cup of coffee, nibble on your croissant while you browse and drop crumbs into a book that you don't even own. Sorry, we don't allow you that kind of luxury. You are not the only tax payer who uses these books therefore, you may not do with them as you please.
Oh and by the way, we love it when you show up and your assignment is due tomorrow. Yea, that is the greatest time ever!! Just to let you know, all of your classmates came before you and took all of the relevant books to your assignment. So yes. All of our books relevant to your topic are checked out. So you will be going home with an encyclopedia. sorry!
How about putting a sentence together? Throwing your library card at me isn't the international sign for "may I reserve a computer?" I can't read your mind.