Here is a worksheet on the Latin root retro. It means back, backward, and behind–but you probably already figured that out. You probably also already understand that this is a very productive root in English, giving us words like retroactive and retrofit.
If you find typos in this document, I would appreciate a notification. And, as always, if you find this material useful in your practice, I would be grateful to hear what you think of it. I seek your peer review.