Passage Four

It’s conventional wisdom in the United States that the American education system is a mess. Since the rest of the world loves to criticize Uncle Sam, that view is held even more strongly elsewhere. But wait a minute. If education really is the source of economic success, as experts continually claim, American schools can’t be too bad. If they were, the American economy would not be the wonder of the world, able to create good jobs at a pace that others can only envy, and with a huge advantage in many of the key technologies of the next centurey. Specially, American high schools can’t be a disaster area. The proof lies in the quality of American universities. In any reasonable ranking of the best 100 universities of the world, the United States would dominate the list. College professors are not alchemists(炼金术士), they cannot turn base metal into gold. (I know; I used to be one.) If the output of American higher education is as good as it seems to be, the input must be a lot better than Americans fear. We can at least be doubtful about some common claims. For example; it’s often said that the United States has a skill shortage in high technology -- and the fact that Silicon Valley recruits (征募) heavily around the world is said to be evidence of that. But without more inquiry, we can’t know whether this is because American college graduates are stupid, or because that hightechnology sector has grown so fast that it cannot possibly satisfy all its demands for high-level skills from the United States.

What is the main idea of this passage