It all happened so fast that I turned around to see what description was used.

Action description. According to the query, official website showed in the question bank that "I turned my head" in the article "Childhood" was an action. It all happened so fast that I turned my head and looked back. The branch from which I just jumped into the yard is still shaking and a yellow leaf is falling from it. This sentence shows the loneliness of the author's inner world.