职称英语《理工类》阅读理解真题练习

　　【摘要】2017年职称英语考试备考中，环球网校为帮助大家备考特分享了“职称英语《理工类》阅读理解真题练习”供大家练习，更多资料敬请关注环球职称英语考试频道，网校会及时更新考试资讯……

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　　OlderVolcanic Eruptions

　　Volcanoes were more destructive in ancient history, not because theywere bigger，but because the carbon dioxide(二氧化碳)theyreleased wiped out life with greater ease.

　　Paul Wignall from the University of Leeds was investigating the linkbetween volcanic eruptions and mass extinctions. Not all volcanic eruptionskilled off large numbers of animals, but all the mass extinctions over the past300 million years coincided with huge formations of volcanic rock. To hissurprise, the older the massive volcanic eruptions were, the more damage theyseemed to do. He calculated the "killing efficiency" for thesevolcanoes by comparing the proportion of life they killed off with the volumeof lava (熔岩) that they produced. He found that sizefor size, older eruptions were at least 10 times as effective at wiping outlife as their more recent rivals

　　The Permian (二叠纪)extinction, for example, which happened 250 million years ago, is marked byfloods of volcanic rock in Siberia that cover an area roughly the size ofwestern Europe. Those volcanoes are thought to have pumped out about 10gigatonnes (十亿吨) of carbon as carbon dioxide. The globalwarming that followed wiped out 80 percent of all marine genera (种类)at the time, and it took 5 million years for the planet to recover. Yet 60million years ago, there was another huge amount of volcanic activity andglobal warming but no mass extindtion. Some animals did disappear but thingsreturned to normal within tens of thousands of years. "The most recentones hardly have an effect at all," Wignall says. He ignored theextinction which wiped out the dinosaurs (恐龙) 65million years ago, because many scientists believe it was primarily caused bythe impact of an asteroid (小行星). Hethinks that older volcanoes had more killing power because more recent lifeforms were better adapted to dealing with increased levels of CO2.

　　Vincent Courtillot, director of the Paris Geophysical Institute in France,says that Wignall's idea is provocative. But he says it is incredibly hard todo these sorts of calculations. He points out that the killing power ofvolcanic eruptions depends on how long they lasted. And it is impossible totell whether the huge blasts lasted for thousands

　　or millions of years. He also adds that itis difficult to estimate how much lava prehistoric volcanoes produced, and thatlava volume may not necessarily correspond to carbon dioxide emissions.

　　41.Older volcanic eruptions did moredamage than more recent ones because

　　A. older volcanoes were brighter.

　　B. carbon dioxide made the earth muchwarmer

　　C. older volcanoes were hotter

　　D. carbon dioxide killed off life moreeasily

　　答案：d

　　42. Wignall calculated the killing powerof those older volcanic eruptions by

　　A. estimating how long they lasted

　　B. counting the dinosaurs they killed

　　C. comparing the proportion of lifekilled with the volume of lava produced

　　D. studying the chemical composition oflava

　　答案：c

　　43. When did dinosaurs become extinct?

　　A. 300 million years ago.

　　B. 250 million years ago

　　C. 65 million years ago

　　D. 60 million years ago

　　答案：c

　　44. It can be inferred from Paragraph 3that the cause of dinosaur extinction is_______

　　A. a political issue.

　　B. self-evident.

　　C. quite certain

　　D. controversial

　　答案：d

　　45. What is the main thesis of thearticle?

　　A. Volcanic eruptions are not alwaysdeadly.

　　B. Carbon dioxide emissions often giverise to global warming.

　　C. Older volcanic eruptions are moredestructive

　　D. It is not easy to calculate the killingpower of a volcanic eruption

　　答案：c

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　　环球网校友情提示：本文整理“职称英语《理工类》阅读理解真题练习”。如果您在此过程中遇到任何疑问，请登录环球网校职称英语频道及职称英语论坛，我们随时与广大考生朋友们一起交流!

　　【摘要】2017年职称英语考试备考中，环球网校为帮助大家备考特分享了“职称英语《理工类》阅读理解真题练习”供大家练习，更多资料敬请关注环球职称英语考试频道，网校会及时更新考试资讯……

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　　Deforestation and Desertification(沙漠化)

　　TheSahel zone lies between the Saharadesert and the fertile savannahs(热带大草原)ofnorthern Nigeria and South Sudan. The word sahel comes from Arabic and means marginal or transitional ,andthis is a good description of thesesemi-arid(半干旱)lands,whichoccupy much of the Western African countries of Mail,Mauritania,Niger,and Chad.

　　Unfortunately, over the last century theSahara desert has steadily crept southwards eating into once productive Sahellands. United Nations surveys show that over 70 percent of the dry land inagriculture use in Africa has deterioratedover the last 30 years. Droughts have become more severe, the most recentlasting over twenty years in parts of the Sahel region. The same process ofdesertification is taking place across southern Africa as the Kalahari desertadvances into Botswana and parts of South Africa.

　　One ofthe major causes of this desert advance ispoor agricultural land use, driven by the pressures of increasing population.Overgrazing一 keeping too many farm animals on the land一means that grasses and other plants cannot recover, and scarce water suppliesare exhausted. Overcultivation一 tryingto grow too many crops on poor land一 resultsin the soil becoming even less fertile and drier, and beginning to break up. Soilerosion (侵蚀) follows, and the land turns into desert.

　　Another cause of desertification is loss of tree cover. Trees are cutdown for use as fuel and to clear land for agricultural use. Tree roots help tobind the soil together, to conserve moisture, and to provide a habitat forother plants and animals. When trees are cut down, the soil begins to dry andloosen, wind and rain erosion increase, other plant species die, and eventuallythe fertile top soil may be almost entirely lost, leaving only bare rock anddust.

　　The effects of loss of topsoil and increased drought are irreversible. Theyare,however, preventable. Careful conservation of tree cover and sustainableagricultural land use have been shown to halt deterioration of soils and lessenthe effects of shortage of rainfall. One project in Kita in south-west Malifunded by UNDP has involved local communities in sustainable management offorest,while at the same time providing a viable(有活力的)agriculturaleconomy. This may be a model for similar projects in otherWest African countries.

　　46 order to prevent desertification,the author proposes ___.

　　A. making good use of international aids

　　B. developing a sustainableagricultural economy

　　C. gaining international support

　　D. converting agricultural land intoforest

　　答案：b

　　47.The Sahel zone is an area which ___.

　　A. is covered with sad and grass

　　B. has a long history

　　C. occupies much of South Nigeria

　　D. belongs to Sudan

　　答案：a

　　48. What is the situation about thedesertification in Africa?

　　A. The deserts are replaced withgrasslands

　　B. The deserts are expanding

　　C. the deserts are moving northwards

　　D. the deserts are being deserted

　　答案：b

　　49. The word “deteriorated ” in paragraph2 means ___.

　　A. deepened

　　B. suffered

　　C. slipped

　　D. worsened

　　答案：d

　　50. What is the root causeof desertification?

　　A. poor farming

　　B. overpopulation

　　C. radical climate change

　　D. disappearance of rare plant species

　　答案：a

　　51. In order to prevent desertification,the author proposes ___.

　　A. making good use of international aids

　　B. developing a sustainableagricultural economy

　　C. gaining international support

　　D. converting agricultural land intoforest

　　答案：b

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2017年职称英语考试复习重点句型汇总

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　　环球网校友情提示：本文整理“职称英语《理工类》阅读理解真题练习”。如果您在此过程中遇到任何疑问，请登录环球网校职称英语频道及职称英语论坛，我们随时与广大考生朋友们一起交流!