题目内容：
回答题：Section A
Directions: In this section, there is a short passage with 5 questions or incomplete statements. Read the passagecarefully. Then answer the questions or complete the statements in the fewest possible words. Please write youranswers on Answer Sheet 2.
Questions 47 to 51 are based on the following passage.
In the second half of the twentieth century, many countries of the South began to send students to theindustrialized countries for further education. They urgently needed supplies of highly trained personnel toimplement a concept of development based on modernization.
But many of these students decided to stay on in the developed countries when they had finished theirtraining. At the same time, many professionals who did return home but no longer felt at ease there also decided to go back to the countries where they had studied.
In the 1960s, some Latin American countries tried to solve this problem by setting up special "return"programs to encourage their professionals to come back home. These programs received support from internationalbodies such as the International Organization for Migration, which in 1974 enabled over 1,600 qualified scientistsand technicians to return to Latin America.
In the 1980s and 1990s,"temporary return" programs were set up in order to make the best use of trainedpersonnel occupying strategic positions in the developed countries. This gave rise to the United NationsDevelopment Program's Transfer of Know/edge through Expatriate Nationals, which encourages technicians andscientists to work in their own countries for short periods. But the brain drain from these countries may wellincrease in response to the new laws of the international market in knowledge.
Recent studies forecast that the most developed countries are going to need more and more highly qualifiedprofessionals around twice as many as their educational systems will be able to produce, or so it is thought. As aresult there is an urgent need for developing countries which send students abroad to give preference to fieldswhere they need competent people to give muscle to their own institutions, instead of encouraging the training ofpeople who may not come back because there are no professional outlets for them. And the countries of the Southmust not be content with institutional structures that simply take back professionals sent abroad; they mustintroduce flexible administrative procedures to encourage them to return. If they do not do this, the brain drain isbound to continue.
The developing countries believe that sending students to the industrialized countries is a good way to _______________
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