单选题 Scholars and students have always been travelers. The official case for "academic mobility" is now often stated in impressive terms as a fundamental necessity for economic and social progress in the world, and debated in the corridors of Europe, but it is certainly nothing new. Serious students were always ready to go abroad in search of the most stimulating teachers and the most famous academies; in search of the purest philosophy, the most effective medicine, the likeliest road to gold.
Mobility of this kind meant also mobility of ideas, their transference across frontiers, their simultaneous impact upon many groups of people. The point of learning is to share it, either with students or with colleagues. One presumes that only eccentrics have no interest in being credited with a startling discovery, or a new technique. It must also have been reassuring to know that other people in other parts of the world were about to make the same discovery or were thinking along the same lines, and that one was not quite alone, confronted by inquisition, ridicule or neglect.
In the 20th century, and particularly in the last 20 years, the old footpaths of the wandering scholars have become vast highways. The vehicle which has made this possible has of course been the airplane, making contact between scholars even in the most distant places immediately feasible, and providing for the very rapid transmission of knowledge.
Apart from the vehicle itself, it is fairly easy to identify the main factors which have brought about the recent explosion in academic movement. Some of these are purely quantitative and require no further mention; there are far more centers of learning, and a far greater number of scholars and students. In addition, one must recognize the very considerable multiplication of disciplines, particularly in the sciences, which by widening the total area of advanced studies has produced an enormous number of specialists whose particular interests are precisely defined. These people would work in some isolation if they were not able to keep in touch with similar isolated groups in other countries.

单选题 What does the author think of the "academic mobility"?

单选题 What happens to a scholar who shares his ideas with his colleagues?

单选题 In what way does the recent development in air travel benefit us according to the passage?

单选题 The writer thinks that academic work has recently become more specialized because ______.

单选题 Which of the following is not considered as the factor which has resulted in the recent explosion in academic movement?