I had an idea that it would involve keyframes (which I haven't yet used), but didn't really know. So, to be clear, I can place as many captions on one slide as I want, and I can use keyframes to time when they appear/move/disappear from the slide?
Kewl! Thanks! Now to go teach myself how...
A flute without any holes is not a flute
A doughnut without any holes is a danish (Caddyshack)