This document contains three lessons:
1. The first lesson discusses relative clauses, which provide additional information about something in a sentence. They can be essential or non-essential information.
2. The second lesson covers auxiliary verbs like "can", "could", "must", and "may" and their uses for ability, permission, requests, and possibility.
3. The third lesson explains the future form "going to", which is used to talk about plans and predictions based on present evidence, such as "I'm going to see him later today" or "It's going to rain soon."