填空题. Throughout the nation's more than 15,000 school districts, widely differing approaches to teaching science and math have emerged. Though there can be strength in diversity, a new international analysis suggests that this variability has instead contributed to lackluster achievement scores of U.S. children related to their peers in other developed countries. 11 Indeed, concludes William H. Schmidt of Michigan State University, who led the new analysis, "no single intellectual 12 coherent vision dominates U. S. educational practice in math or science." The reason, he said, "is because the system is deeply and fundamentally flawed." The new analysis, which released this week by the National 13 Science Foundation in Arlington, Va., is based on data collecting 14 from about 50 nations as part of the Third International Mathematics and Science Study. Not only approaches to teaching science and math vary among 15 individual U. S. communities, the report finds, but there appears to be a little strategic focus within a school district's curricula, its 16 textbooks, or its teachers' activities. This contrasts sharply with the coordinated national programs of most other countries. In average, U. S. students study more topics within science 17 and math than their international counterparts do. This creates an educational environment where "is a mile wide and an inch deep," 18 Schmidt notes. For instance, eighth graders in the United States cover about 33 topics in math versus just 19 in Japan. Among science courses, the international gap is even wide. U. S. curricula for this age level 19 resemble those of a small group of countries including Australia, Thailand, Iceland, and Bulgaria. Schmidt asks whether the United States wants to be classed with these nations, whose educational systems "share our pattern of splintered visions" and which are not 20 economic leaders.