Please answer the following question: Generate a question about the following movie plot: In 1947, Stingo relocates to Brooklyn in order to write a novel and is befriended by Sophie Zawistowski, a Polish immigrant, and her emotionally unstable lover, Nathan Landau. One evening, Stingo learns from Sophie that she was married but her husband and her father were killed in a German work camp and that she was interned in the Auschwitz concentration camp. Nathan is constantly jealous, and when he is in one of his violent mood swings he convinces himself that Sophie is unfaithful to him and he abuses and harasses her. There is a flashback showing Nathan with Sophie who is near death due to anemia shortly after her immigration to the U.S. Sophie eventually reveals that her father was a Nazi sympathizer. Sophie's wartime lover, Jozef, who lived with his half-sister, Wanda, was a leader in the Resistance. Wanda tried to convince Sophie to translate some stolen Gestapo documents, but Sophie declined, fearing she might endanger her children. Two weeks later, Jozef was murdered by the Gestapo, and Sophie was arrested and sent to Auschwitz with her children. Nathan tells Sophie and Stingo that the research he is doing at a pharmaceutical company is so groundbreaking that he will win the Nobel Prize. At a meeting with Nathan's physician brother, Stingo learns that Nathan is a paranoid schizophrenic and that all of the schools that Nathan had attended were "expensive funny farms." He has a job in the library of a pharmaceutical firm, which his brother got for him, and only occasionally assists with research. After Nathan discharges a firearm over the telephone in a violent rage, Sophie and Stingo flee to a hotel. She reveals to him that, upon arrival at Auschwitz, she was forced to choose which one of her two children would be gassed and which would proceed to the labor camp. To avoid having both children killed, she chose her son, Jan, to be sent to the children's camp, and her daughter, Eva, to be sent to her death. Sophie and Stingo make love, but while Stingo is sleeping Sophie returns to Nathan. Sophie and...
Answer:
What does Stingo learn about Nathan?