In the United States the way people spend their leisure time is an important part of their identity．Perhaps everybody does nearly the same thing all day in the office or the factory, but leisure time is what makes people distinct and reveals who they are．Some people like rock music, for example, and others may like jazz or classical music．Some people are runners or swimmers, and others are 'couch (睡椅) potatoes' who 'surf' the television channels with a remote control Some go to museums while others spend long hours at a shopping centre．These kinds of choices are ways that people define themselves.
It hasn't always been this way．'Leisure time' was almost unknown in the United States in the eighth and nineth centuries．When most people worked on farms, the workday was from sunrise to sunset every day except Sunday, which was devoted to church．Later, with the rise of factories and city populations, people worked equally long hours and had only Sunday for rest．Some people did more of the things than that they do now—attend concerts, have parties, go to restaurants, read novels, or play, sports—but to a much lesser extent.
Slowly, throughout the twentieth century, leisure time grew．Technology made farm work less burdensome, and changes in laws shortened the factory work day and week．New inventions such as the phonograph(留声机)and the radio gave people access to music and mass entertainment on a scale unknown before．People gradually became consumers of entertainment, and businesses competed fiercely for their dollars.
For many people leisure time means going somewhere—to a museum, to a concert, to a restaurant, or to a baseball , for example．Or it means doing something such as playing volleyball, backpacking, swimming, biking, or playing in a park with their children．For other people free time means staying home with wonderful sources of entertainment, such as a VCR, stereo (立体声系统) , or cable TV with dozens of channels．Others pursue creative activities such as cooking, gardening, and home improvement．The latest stay-at-home activity is 'surfing the net'—that is looking for information and entertainment on the Internet.
People in the United States are basically not much different from others in what they do in their leisure time．The real difference may lie in the energy, time, money, and sheer enthusiasm that they devote to it.
'Couch potatoes' in Paragraph 1 refers to those who ______.