Pollution Sources and causesAir pollution comes from both natural and man made Though globally man made pollutants from combustion， construction， mining， agriculture and warfare are increasingly significant in the air pollution Motor vehicle emissions are one of the leading causes of air China， United States， Russia， Mexico， and Japan are the world leaders in air pollution Principal stationary pollution sources include chemical plants， coal-fired power plants， oil refineries， petrochemical plants， nuclear waste disposal activity， incinerators， large livestock farms (dairy cows， pigs， poultry， )， PVC factories， metals production factories， plastics factories， and other heavy Agricultural air pollution comes from contemporary practices which include clear felling and burning of natural vegetation as well as spraying of pesticides and herbicidesAbout 400 million metric tons of hazardous wastes are generated each The United States alone produces about 250 million metric Americans constitute less than 5% of the world's population， but produce roughly 25% of the world’s CO2， and generate approximately 30% of world’s In 2007， China has overtaken the United States as the world's biggest producer of CO2污染源和原因空气污染来自于自然和人为来源。虽然从全球人造燃烧，建筑，采矿，农业和战争污染物空气污染日益方程显着。机动车排放是造成空气污染的主要原因之一。中国，美国，俄罗斯，墨西哥和日本是世界上空气污染排放的领导人。固定污染源主要包括化学工厂，燃煤电厂，炼油厂，石化厂，核废物处置活动，焚烧炉，大牲畜养殖场（奶牛，猪，家禽等），聚氯乙烯厂，金属生产厂，塑料工厂等重工业。空气污染来自农业，其中包括明确的砍伐和自然植被燃烧以及喷洒农药和除草剂的当代实践约400万公吨的危险废物每年产生。仅美国生产约250万公吨。美国人占不到5％的世界人口，但产生大约25世界的二氧化碳％，并产生约30世界的浪费％。 2007年，中国已经超过美国成为世界上最大的二氧化碳生产国美国
Pollution has been a serious problem for a certain time around the There are many causes for Transportation is the main factor of When the waste gas from cars is released， the air is People breathing in the polluted air can develop respiratory Another factor is that people throw their garbage All kinds of garbage not only spoil the splendid environment， but also cause environmental What's more， industrial pollution also deserves our Wastewater from factories is poured into rivers and this causes water As a consequence， the greenhouse effect becomes a problem which needs our immediate caution and how to solve is urgent all over the At present， some measures have been taken to For example， people classify the garbage and some is recycled after being People are also encouraged to use paper products instead of plastic products because we know that our living condition will be worse if we keep ignoring this And I believe we can prevent pollution if everyone makes the 污染已经成为一定时期内时间范围内的一个严重问题。 原因很多，交通玉树是主要原因，当汽车排出废气时，空气就被污染了，人们呼吸了被污染的空气，会导致呼吸道疾病。 另外一个原因就是人们随处乱扔垃圾，不仅破坏了美观的环境，还污染了环境。 还有，工业污染也应该受到我们的关注。工业废水排入河流，引起水污染。 温室效应已经成为需要我们立即采取措施并加以解决的问题，而且解决这个问题也是全世界面临的迫切问题。 现在已经出台了一些措施。比如，人们将垃圾分类，回收并循环利用。 还要鼓励人们使用纸质用品代替塑料。 因为我们知道，如果我们仍然忽略这个问题，生活条件将会恶化，我坚信如果每个人都努力的话，我们就一定能防止污染。：）
Directions: For this part， you are allowed 30 minutes to write a composition based on the following graph showing the growth of the world's The opening sentence is given and you are required to develop it into a full Your part of writing should be no less than 120 Some useful words and phrases are provided， but you do not have to include all of (Suggested words and phrases: birth control， death rate， population explosion， food shortage)The Problem of Human Population It has been estimated that a thousand years ago there were less than 400 million people on Today， however， the world's population has amounted to 5，000 What is worse， it keeps growing at a surprising If this trend continues， the world's population will shoot up to 7，000 million by the year This is what we call population The rapid development of science and technology is the main cause of population We can see that the population has been growing at a tremendous speed since the Industrial and Agriculture Revolution in 1650， which raised the people's standard of living， and the emergence of modern medicine in 1550， which lowered the people's death Population explosion will result in a lot of such problems as food shortage， housing shortage and It is time that we acted quickly to carry out the policy of birth control otherwise， man's survival on the earth will be 你再改改就应该没问题了
Pollution As the world is getting more densely populated， pollution presents a severe More people make more All this waste is polluting our Pollution has a bad influence on our The air is pollnted by the smoke and fog coming out of the factory Plants die for want of fresh The river is polluted and the fish are unfit to There is noise pollution made by cars and factories， etc， which hurts the It is high time we did something about I suggest more trees be planted to keep the air We should purify the water and make use of the wastes and turn harm into By cur common efforts， we will make a clean and purified environment for life and 污染 随着世界人口密度的增长，污染成了严重问题。人多产生的废物就多。所有的垃圾都在污染环境。 污染严重地影响我们的生活。工厂的烟囱里冒出的烟雾污染空气。植物由于缺少新鲜空气而枯死。河流污染，鱼不能生存。汽车、工厂发出噪音对人耳有害。 是对污染采取措施的时候了。我建议多植树以保持空气新鲜。我们应该使水净化，利用废物，转害为利。 通过共同努力，我们将创造一个清洁、美丽的生活、工作环境。
