The document discusses active and passive sentences, as well as root words, prefixes, and suffixes. Active sentences follow the subject-verb pattern and show what the subject is doing, while passive sentences focus on what happened and can omit or reveal who did the action using "by". Prefixes are added to the beginning of words to change their meaning, and you can determine a prefix's meaning by analyzing words that share it. Suffixes are added to the end of words to change grammar, such as indicating an action or adding an "er" or "est" for comparisons.