You want to show that you've seriously imagined yourself taking on the role — something that would likely prompt some questions on your end. However, you want to be as sure as possible that you thoroughly understand the job at hand, what you would expect, and that you'd be ready, willing, and able to take it on. In other words, asking questions is your chance to make sure the job is the right fit for you, not to mention that it has the potential make your prepared answers really come to life in the interview — so don't forfeit the opportunity to stand out.