In a democratic society citizens are encouraged to form their own opinions on candidates for public office, taxes, constitutional amendments, environmental concerns, foreign policy, and other issues. The opinions held by any population are shaped and manipulated by several factors: individual circumstances, the mass media, special-interest groups, and opinion leaders.
Wealthy people tend to think differently on social issues from poor people. Factory workers probably do not share the same views as white-collar, nonunion workers. Women employed outside their homes sometimes have perspectives different from those of full-time homemakers. In these and other ways individual status shapes one’s view of current events.
The mass media, especially television, are powerful influences on the way people think and act. Government officials note how mail from the public tends to "follow the headlines. " Whatever is featured in newspapers and magazines and on television attracts enough attention that people begin to inform themselves and to express opinions.
The mass media have also created larger audiences for government and a wider range of public issues than existed before. Prior to television and the national editions of newspapers, issues and candidates tended to remain localized. In Great Britain and West Germany, for example, elections to the national legislatures were usually viewed by voters as local contests. Today’s elections are seen as struggles between party leaders and programs. In the United States radio and television have been beneficial to the presidency. Since the days of Franklin D. Roosevelt and his "fireside chats," presidents have appealed directly to a national audience over the heads of Congress to advocate their programs.
Special-interest groups spend vast sums annually trying to influence public opinion. Public utilities, for instance, tried to sway public opinion in favor of nuclear power plants. Opposed to them were citizens’ organizations that lobbied to halt the use of nuclear power. During the 1960s the American Medical Association conducted an unsuccessful advertising campaign designed to prevent the passage of Medicare.
Opinion leaders are usually such prominent public figures as politicians, show-business personalities, and celebrity athletes. The opinions of these individuals, whether informed and intelligent or not, carry weight with some segments of the population. Some individuals, such as Nobel Prize winners, are suddenly thrust into public view by the media. By quickly reaching a large audience, their views gain a hearing and are perhaps influential in shaping views on complex issues.
The passage is mainly about（）
A. the forces that influence people’s opinions
B. the freedom of speech in a democratic society
C. the necessity to uphold one’s own opinion on an issue
D. the techniques of talking to a large audience via the mass media
，试类比乙醇中—OH和乙酸中—COOH的性质，回答下列问题：