I don remember you mentioning [some term or name or idea from the study guides] in class. What is it?
I will usually answer specific questions about terms or ideas, especially if they are on the study guides and you missed them in class. But you should also be sure to check the textbook (there is a very good index and glossary) as well as the sourcebook. It may be that I decided I didn’t have time to mention something in class because it was covered in the reading: this does not mean it won’t show up on an examination. Try to use your own resources as well as using mine.