Like all other living beings, humans have clearly changed their environment, but they have done so generally on a grander scale than have other species. Some of these changessuch as the destruction of the worlds tropical rain forests to create grazing land for cattle or the drying up of almost three-quarters of the Aral Sea, once the worlds fourth-largest freshwater lake, for irrigation purposeshave led to altered climate patterns, which in turn have changed the distribution of species of animals and plants.
Scientists are working to understand the long-term consequences that human actions have on ecosystems, while environmentalistsprofessionals in various fields, as well as concerned citizens in the United States and other countriesare struggling to lessen the impact of human activity on the natural world.
Population Growth(人口增长)
Human population growth may be seen to be at the root of virtually all of the worlds environmental problems. Increasingly large numbers of people are being added to the world every year. As the number of people increases, more pollution is generated, more habitats are destroyed, and more natural resources are used up. Even if new technological advances were able to cut in half the environmental impact that each person had, as soon as the worlds population size doubled, the earth would be no better off than before.
The Population Division of the United Nations predicts that the 5.63 billion humans alive in
雅思口语6分的评分标准:Fluency
雅思口语经典话题整理
澳大利亚雅思口语真题整理
雅思口语天天练:过去、现在和将来
雅思口语Part 1的答题要点
雅思口语评分标准:口语流利度的练习
雅思口语素材:名人名言-丘吉尔
雅思口语Part2话题范文:clothing or jewelry
雅思口语高分范文:a shopping centre
雅思口语分类词汇:调味品
雅思口语高频话题整理汇总
雅思口语高分范文:electrical appliance
哈尔滨沈阳西安济南合肥部分雅思口语考官特点介绍
雅思口语7分范文:hometown
雅思口语高分答题技巧:谚语答题法
雅思口语高分模板:回到过去
雅思口语范文赏析
雅思口语考场的三点应对技巧
雅思口语Part2高分范文:a small shop
雅思口语高分范文:person admired
雅思口语素材:名人名言-爱迪生
雅思口语话题模板:父亲节
雅思口语考试的蹲点策略
雅思口语高分必备的6个细节
雅思口语分类词汇:水果
雅思口语素材:名人名言
雅思口语7分技巧:妙用词性转换
雅思口语Part2高分范文:ideal home
雅思口语天天练:怎样回答How are you?
雅思口语Part 1&2的必备话题总结
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