Non-fiction writing: refers to the writing background of "experience the facts", adhering to the "honesty principle", emphasizing the unique sense of presence and realism, is a type of literary creation. Which of the following is non-fiction? ['In recent years, the domestic film and television industry has a special interest in the secret history of the court, and many film and television works are based on real events contained in historical books. Well-documented historical materials have become an important source of such film and television creation.', 'In order to truly reproduce the main details of a bizarre homicide, the writer Ake personally went to the town where the case took place, conducted a field investigation for more than two years, and finally wrote his famous work "The Beginning and End of a Small Town".', 'Cao Xueqin not only has serious and profound philosophical thinking about social life, but also carefully observes the different destinies of himself and ordinary people around him. These real stories provide rich material for his creation of "A Dream of Red Mansions".', 'Many scholars studying rural issues in China have been stationed in the countryside for many years, and have written monographs based on field survey data. This is obviously different from the style of academic writing that likes to use foreign popular theoretical methods.']