This document discusses the prefixes "pre-" and "re-". It explains that pre- means before or prior to and provides examples like pretest and preheat. It then asks the reader to determine what prewash means. It also explains that re- has two meanings: to do again or to go back to the original state. Examples are given like review, reuse, and reheat. Finally, it provides words with the re- prefix and asks the reader to determine their meanings, such as redo, rewrite, and retie.