案例分析题Invention and innovation have been quintessentially American pursuits from the earliest days of the republic. Benjamin Franklin was a world-famous scientist and inventor. Cyrus McCormick and his harvester, Samuel F. B. Morse and the telegraph, Alexander Graham Bell and the telephone—the 19th century produced a string of inventors and their world-changing creations. And then there was the greatest of them all, Thomas Alva Edison. He came up with the crucial devices that would give birth to three enduring American industries:electrical power, recorded music and motion pictures. Much of the world we live in today is a legacy of Edison and of his devotion to science and innovation. Edison taught us to invent, and for decades we were the best in the world. But today, more than 160 years after Edison’s birth, America is losing its scientific edge. A landmark report released in May by the National Science Board lays out the numbers:while U. S. investment in R&D as a share of total GDP has remained relatively constant since the mid-1980s at 2.7% , the federal share of R&D has been consistently declining—even as Asian nations like Japan and South Korea have rapidly increased that ratio. At the same time, American students seem to be losing interest in science. Only about one-third of U. S. bachelor’s degrees are in science or engineering now, compared with 63% in Japan and 53% in China. It’s ironic that nowhere is America’s position in science and technology more threatened than in the industry that Edison essentially invented: energy. Clean power could be to the 21st century what aeronautics and the computer were to the 20th, but the U. S. is already falling behind. Meanwhile, Congress remains largely paralyzed. Though in May the House of Representatives was finally able to pass the $ 86 billion America Competes Reauthorization Act, which would double the budgets of the National Science Foundation (NSF) and Energy Department’s Office of Science, the bill’s fate is cloudy in the deadlocked Senate. "At this rate... we’ll be buying most of our wind generators and photovoltaic panels from other countries, " former NSF head Arden L. Bement said at a congressional hearing recently. "That’s what keeps me awake sometimes at night. " Some erosion of the U. S. ’s scientific dominance is inevitable in a globalized world and might not even be a bad thing. Tomorrow’s innovators could arise in Shanghai or Seoul or Bangalore. And Edison would counsel against panic—as he put it once, " Whatever setbacks America has encountered, it has always emerged as a stronger and more prosperous nation. " But the U. S. will inevitably decline unless we invest in the education and research necessary to maintain the American edge. The next generation of Edisons could be waiting. But unless we move quickly, they won’t have the tools they need to thrive. The main purpose of this passage is to （）.

A. restore American students’interest in science
B. keep American alert to the rise of other nations
C. warn American of the decline of their scientific edge
D. urge government to invest more in education and research