[单项选择]It might seem natural to gauge the amount of discrimination in labor markets by looking at the average wages of different groups. For instance, in recent years the wage of the average black worker in the U.S. has been about 20 percent less than the wage of the average white workers. The wage of the average female worker has been about 30 percent less than the wage of the average male worker. These wage differentials are sometimes presented in political debate as evidence that many employers discriminate against blacks and women. Yet there is an obvious problem with this approach. Even in a labor market free of discrimination, different people have different wages. People differ ill the amount of human capital they have and in the kinds of work they are able and walling to do. The wage differences we observe in the economy are, to a large extent, attributable to the determinants of equilibrium wages. Simply observing differences in wages among broad groups say little about the prevalenc
A. 13%
B. 55%
C. 68%
D. 61%

[单项选择]It might seem natural to gauge the amount of discrimination in labor markets by looking at the average wages of different groups. For instance, in recent years the wage of the average black worker in the U.S. has been about 20 percent less than the wage of the average white workers. The wage of the average female worker has been about 30 percent less than the wage of the average male worker. These wage differentials are sometimes presented in political debate as evidence that many employers discriminate against blacks and women. Yet there is an obvious problem with this approach. Even in a labor market free of discrimination, different people have different wages. People differ ill the amount of human capital they have and in the kinds of work they are able and walling to do. The wage differences we observe in the economy are, to a large extent, attributable to the determinants of equilibrium wages. Simply observing differences in wages among broad groups say little about the prevalenc
A. Even in a labor market freedom is valued, different people have different wages.
B. Even in a labor market full of discrimination, different people have different wages.
C. Even in a labor market with discrimination, different people have different wages.
D. Even in a labor market without discrimination, different people have different wages.

[单项选择]A cramped public-school test kitchen might seem an unlikely outpost for a food revolution. But Collazo, executive chef for the New York City public schools, and scores of others across the country -- celebrity chefs and lunch ladies, district superintendents and politicians -- say they’re determined to improve what kids eat in school. Nearly everyone agrees something must be done. Most school cafeterias are staffed by poorly trained, badly equipped workers who churn out 4.8 billion hot lunches a year. Often the meals, produced for about $1 each, consist of breaded meat patties, French fries and overcooked vegetables. So the kids buy muffins, cookies and ice cream instead -- or they feast on fast food from McDonald’s, Pizza Hut and Taco Bell, which is available in more than half the schools in the nation. Vending machines packed with sodas and candy line the hall ways. "We’re killing our kids" with the food we serve, says Texas Education Commissioner Susan Combs.
As rates of child
A. most American school cafeterias are well functional.
B. more than half the schools have McDonald chains.
C. to change school food has been agreed by nearly everyone.
D. fast food restaurants are beneficial supplements to school cafeterias.