... renew a book?
... request something the library doesn't have?
... see what I have checked out from the library right now?
... return something when the library is closed?
... find out if a book is on reserve for my class?
... find out if the library has the book I need?
... find out if the library has the article I need?
... find the "Stacks", "Serials", "Storage Area", etc.?