In Chapter 31, comment on the way the author summarizes earlier events to show their significance.

Well, the first way Lee summarizes earlier events is briefly. The entire chapter is only a few pages long, and the summaries don't take up much of that. Second, Lee does so by having Scout review (and re-view—re-see) those events in light of what Boo had done for her before saving her. The result (and third way) is that she reaches a conclusion about the events' meaning. Before the actions had been mysteries; now they clearly mean friendship.