Answer: He uses a dramatic narrative tone and describes the character's daily routine in the house, as well as their personalities and reactions so that when the supernatural events happen, it is natural for them.
Explanation: Narrative tones portray the writer's attitude or the genre of the story. Cortázar uses a dramatic narrative tone so that the reader gets involved in the ambiance from the beginning and repares for thrilling events. He also describes their daily activities, personalities, and reactions in detail. By the time the supernatural events occur, the reader is already immersed in the storyline and processes them as "normal situations" that happen naturally in that world.
