Answer: (1) Various public relations have different attitudes towards the public. In the era of no public relations, monopoly oligarchs only care about their own interests, and the public is the object of their slaughter. One-way boasting of public relations is characterized by "the public will be fooled"; One-way communication is characterized by "informing the public"; Two-way communication public relations has developed into "investing in the public"; The two-way symmetric public-private relationship further puts forward that "public will can participate in decision-making". (2) Principles of various public relations. Different oligopolies believe in "going their own way" and "blocking information from the public"; One-way boastful public relations, insisting on "all propaganda has the final say", regardless of public interests; One-way communication public relations adheres to the principles of "openness of facts" and "telling the truth" to increase public trust in the organization; The two-way communication between the public and the public insists on letting the organization know the public and the public know the organization, "increasing the transparency of both sides"; Two-way symmetrical public-private relations insist that organizations and the public should be symmetrical and balanced in purpose, interest and communication. (3) Various public relations adopt different methods. Oligarches control public opinion by blocking, intimidating and buying off the press; One-way boastful public relations adopts the method of fabricating "myth" and making news; One-way public relations adopts the method of providing accurate and valuable information to the public; Two-way communication public relations adopts the methods of investigation and research and two-way communication; Two-way symmetrical public-private relations adopt the methods of monitoring, publishing, feedback, adjustment and two-way balance. (4) The purpose of all kinds of public relations is to monopolize the world; The purpose of one-way boasting about public relations is to play with the public in order to expand its influence; The purpose of one-way communication is to seek public understanding, recognition and acceptance; Public relations two-way communication is to win public support and please the public; The two-way symmetrical public-private relationship is for the benefit of both parties and harmonious development. The slogan of the two-way symmetrical relationship between the public and the public seems to be less appealing than the slogan of the two-way communication relationship between the public and the public, and it feels that the public position is higher, but the two-way symmetrical relationship between the public and the public is more rational, objective and true. Because in the real society, especially under the condition of commodity economy, everything people fight for is related to their interests. Therefore, people will regard "all for the public" as a moving slogan, not a code of conduct. From this point of view, the two-way symmetric model is more objective and real, so it is more vital.