研究生英语课程unit7.doc

Unit 7
Text A
II. Language points
1. During the second half of the twentieth century, the impact of social and environmental factors on infectious disease outbreaks has been greatly amplified by the doubling of the world’s population, accelerating most rapidly in the developing countries of the tropics and subtropics, where infectious diseases continued to have a hold. (Para. 1) During the second half of the twentieth century, social and environmental factors have had an increasingly strong impact on infectious disease outbreaks, due to the sharp increase in the world’s population, which grows most rapidly in the developing countries of the tropics and subtropics, where infectious diseases continued to cause suffering.
amplify v. to increase sth. in strength
e. g. A manufacturer can amplify the demand of a product by advertising widely.
accelerate v. to start to go faster
e. g. We must seize all opportunities to accelerate development.
2. Rural–urban migration has resulted in inadequacy of sanitation, crowded living conditions and other basic infrastructure issues associated with population growth. (Para. 1) Large numbers of people have moved from the countryside to cities, causing problems such as dirty and crowded living conditions and lack of basic and necessary public service systems.
migration: n. the movement of large numbers of people, birds or animals from one