A、正确 B、错误 B事实细节的找寻和判断。根据原文the differences are not limited to the United States可知这一差别并非只出现在美国。由此可见，题干说法与原文相符，是正确的。

In April, the Manhattan Institute released its yearly study of graduation rates. The research group used information from 2003. The researchers found that 72 percent of girls successfully completed their high school education. That compared to 65 percent of boys. The newspaper Education Week noted earlier this year that, in some ways, what people are worried about now is really not new. Boys have scored lower than girls on tests in the National Assessment of Educational Progress since at least 1971.
    And the differences are not limited to the United States. Education Week noted the results of an international reading test in 2003.  Fifteen-year-olds took the test in 41 countries. Girls scored higher than boys in almost every country. Differences between males and females are a continuing issue of fierce debate. Cultural and economic influences play an important part. But recent findings suggest that another part of the answer lies in differences between the male and female brains.
    These include differences in learning rates. As a result, some researchers say, boys may not be able to develop language and reading skills as well as girls do. The last time there was a lot of concern about differences in school, it was about girls, especially in math and science classes. Efforts to improve the situation for girls included hiring more female teachers. Yet some people think the opposite situation exists now. They say not enough male teachers is one reason why boys may not learn as well in class. Another explanation being heard involves the increased testing in American schools. Some people say schools are preparing for these important tests by forcing boys to sit quietly at their desks. They say this is unfair. Still others say that society is failing boys, by giving them the message that studying is not manly. And others say boys are failing in school because they become too interested in the girls in their classes. One attempt to solve problems like these is the use of same-sex classrooms.