After learning each lesson, users can share their thoughts and opinions about the knowledge they just absorbed. If the comment is approved, users will earn 15 points of rewards. Comments are categorized into single lessons. Users can only join to comment after they finish each lesson. We set a rule for the length of each comment to be at least 350 characters. We have a team to review all the comments to ensure there's no spam. This is another way to accumulate points. We treasure your comments because the more you reflect on the knowledge, the more you understand the lesson.