Over the past three decades the number of students leaving home each year to study abroad has grown at an annual rate of 3.9 percent, from 800,000 in 1975 to 2.5 million in 2004. Most travel from one developed nation to another, but the flow from

Over the past three decades the number of students leaving home each year to study abroad has grown at an annual rate of 3.9 percent, from 800,000 in 1975 to 2.5 million in 2004. Most travel from one developed nation to another, but the flow from developing to developed countries is growing rapidly .

大多数人都是从一个发达国家留学到另一个发达国家，但从发展中国家到发达国家留学的人数也在迅速增加。（考点：并列句的正确翻译）