20.A rising population is one of the main reasons that there is global warming.Between 1650and 1850the population increased by 0.75billion people going from 0.25billion to one billion.From 1930to the end of the century the population rose from two billion to over six billion.In just a third of the time the population rose by more than five times what it did before.It is expected that this trend in the changing population will continue and could even heighten.The growing population requires increasing amounts of energy.These energy demands and other supplies require production,which almost always involves the emission of greenhouse gases.The more the population increases the more greenhouse gases that are produced and the greater the increase in temperature.
The burning of fossil fuels is one of the best-known causes for global warming.The major reason for fossil fuels contributing so much to global warming is the release of carbon that occurs during the burning of fossil fuels.When people burn fossil fuels,they release large amounts of carbon by way of the release of carbon dioxide.The carbon dioxide in the air then leads to global warming.
Another source of carbon dioxide comes from deforestation.In forests there is a large amount of carbon that is stored in the trees and other plants.This carbon is out of the atmosphere because the trees consume the carbon from carbon dioxide.When people cut down trees,they are frequently burned.This burning releases the carbon dioxide into the atmosphere that was stored in organic matter.Even when new trees are planted,it can take up to one hundred years to make up for the carbon that was released.It is commonly thought that because trees absorb more carbon dioxide,the atmosphere experiences positive effects.
Sophie Armstrong,the writer of Earth Care put it,"There's no doubt that the earth is becoming warmer because of human activity rather than a random but natural phenomenon.
21.Which of the following titles goes with the text?C
A.A Rising Population
B.Saving Sources of Energy
C.Global warming:The causes
D.Carbon Dioxide
22.The underlined word"deforestation"meansD.
A.rising population
B.burning of fossil fuels
C.greenhouse gas
D.cutting down or burning trees.
23.To sum up from the passage,it isA that has caused global warming.
A.human activity
B.sources of energy
C.natural forces
D.the polluted atmosphere
24.Which column of a website might the passage come from?C
A.Economy.
B.Art
C.Environment
D.Health.
分析 本文主要讲述了全球变暖的几个原因:人口增长,矿物燃料燃烧,滥砍滥伐,归根结底是人类活动造成了全球变暖.
解答 21-24 CDAC
21. C 标题判断题.本文主要讲述了全球变暖的几个原因:人口增长,矿物燃料燃烧,滥砍滥伐,归根结底是人类活动造成了全球变暖.因此C项"全球变暖的原因"概括了文章主旨,是最佳标题.故选C.
22.D 词义猜测题.画线词所在句是该段的中心句.该段主要介绍了树木和植物中储存着大量的二氧化碳,树木消耗二氧化碳中的碳原子,释放出氧气,如果砍掉树木,二氧化碳就大量释放到空气中去,因此推断二氧化碳的另一个主要来源是滥砍滥伐.所以画线词的意思与D项意思接近.故选D.
23.A 细节理解题.根据最后一段Sophie Armstrong的陈述"There's no doubt that the earth is becoming warmer because of human activity rather than a random but natural phenomenon."可知,是人类的活动导致了全球变暖.故选A.
24.C 推理判断题.本文主要讲述了全球变暖的原因,属于环境保护范畴,因此推断,这篇文章可能来自网站上的环境栏目.故选C.
点评 阅读理解题测试考生在阅读基础上的逻辑推理能力,要求考生根据文章所述事件的逻辑关系,对未说明的趋势或结局作出合理的推断;或根据作者所阐述的观点理论,对文章未涉及的现象、事例给以解释.考生首先要仔细阅读短文,完整了解信息,准确把握作者观点.