Alright, here is a worksheet on the Greek word root pro, which means before, forward, forth, in place of, and in addition to. This root is so productive in English–as this worksheet shows in summary–that I hardly need mention it. Interestingly, in Russia, this root shows up as a preposition meaning “about.”
Editorially speaking, let me just say this: adding pro to other words, such as active, a perfectly serviceable adjective per se, improves neither the root nor the word to which it added. It does, as Paul Fussell once commented, contribute to the average American’s mistaken perception of themselves as smarter for having added a syllable to a word. Proactive does not mean, alas, anymore than active does.
Let’s leave pro to words like prokaryote.
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.