[单项选择] Labor Force The labor force is the part of a nation’’s population that works for pay or that is looking for a paying job. In 1800, the United States had about 2 million people in its labor force. Most of them worked on farms, most of whom were men. In 1993, about 130 million Americans were in the labor force. 96 million workers were found in large cities, 46 percent of whom were women. New Kinds of Jobs In the twentieth century, the U. S. labor force has undergone many changes. One of the most significant of these changes is in the decline in the number of blue collar jobs and the rise in the number of white-collar jobs. A blue-collar job involves manual or outdoor labor. Blue-collar workers include factory assemblers and welders; carpenters, plumbers(水暖工), mechanics, and painters; construction workers, and truck drivers. Although the number of blue-collar workers increased in the twentieth century, the future will see a declining need
A. Y
B. N
C. NG