"Remember me, right?", "Guess what my name is?", "When was the last time I came here?", "How old am I?", "What day is this?", Or "Come on ... you must know the answer. Try thinking harder. "
Your intention may be to provoke her memory. However, do not bombard with a lot of questions. In addition to worry, this is also not useful. Some people may really not remember even the trivial ones. So, think carefully before you ask the obvious questions they can not answer. Better tell him about the memories you've done together.