求翻译：随着世界人口越来越密集（densely populated),空气污染已经成了严重的问题。空气污染主要来源于四个主要的人类活动领域：工业、能源业、交通运输业以及农业。经营工厂,为火车、飞机和公共汽车提供动力都需要能源。几乎所有这些能源都是通过燃烧燃料产生的,这就会造成空气污染。科学家们正在研究能减少环境破坏的新发电方式。公共环保意识的增强促成了诸如回收利用(recycling)等活动的产生。是什么意思？

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As the world population density (densely populated), air pollution has become a serious problem. The main sources of air pollution in four main areas of human activity: industry, energy, transport and agriculture. Operating factories, to train, aircraft and buses are required to provide the impetus

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As the world population more and more intensive (densely populated), air pollution has become a serious problem. Air pollution comes mainly from human activities of the four main areas: industry, energy, transport and agriculture. Operates a factory, to power the trains, planes and buses requires en

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