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 本文主要講述了全球變暖的幾個原因:人口增長,礦物燃料燃燒,濫砍濫伐,歸根結(jié)底是人類活動造成了全球變暖.
解答 21-24 CDAC
21. C 標題判斷題.本文主要講述了全球變暖的幾個原因:人口增長,礦物燃料燃燒,濫砍濫伐,歸根結(jié)底是人類活動造成了全球變暖.因此C項"全球變暖的原因"概括了文章主旨,是最佳標題.故選C.
22.D 詞義猜測題.畫線詞所在句是該段的中心句.該段主要介紹了樹木和植物中儲存著大量的二氧化碳,樹木消耗二氧化碳中的碳原子,釋放出氧氣,如果砍掉樹木,二氧化碳就大量釋放到空氣中去,因此推斷二氧化碳的另一個主要來源是濫砍濫伐.所以畫線詞的意思與D項意思接近.故選D.
23.A 細節(jié)理解題.根據(jù)最后一段Sophie Armstrong的陳述"There's no doubt that the earth is becoming warmer because of human activity rather than a random but natural phenomenon."可知,是人類的活動導致了全球變暖.故選A.
24.C 推理判斷題.本文主要講述了全球變暖的原因,屬于環(huán)境保護范疇,因此推斷,這篇文章可能來自網(wǎng)站上的環(huán)境欄目.故選C.
點評 閱讀理解題測試考生在閱讀基礎上的邏輯推理能力,要求考生根據(jù)文章所述事件的邏輯關(guān)系,對未說明的趨勢或結(jié)局作出合理的推斷;或根據(jù)作者所闡述的觀點理論,對文章未涉及的現(xiàn)象、事例給以解釋.考生首先要仔細閱讀短文,完整了解信息,準確把握作者觀點.