作者：圣才电子书
出版社：圣才电子书
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2019年全国职称英语等级考试（理工类A级）题库【历年真题＋章节题库＋模拟试题】试读：
第一部分 历年真题
2016年全国职称英语等级考试理工类A级真题及详解
第1部分：词汇选项（第l～15题，每题l分，共15分）
下面每个句子中均有1个词或者短语划有底横线,请为每处划线部分确定1个意义最为接近的选项.
1. The revelation of his past led to his resignation.
A. imagination
B. confirmation
C. recall
D. disclosure【答案】D【解析】句意：对他过去的揭露导致了他的辞职。revelation揭发，暴露。 disclosure泄露，揭露。二者意思相近，此处可互相替换，因此选D项。imagination想像，想像力。confirmation证实；证明； 确认。recall召回，唤回；回想。
2. Jensen is a dangerous man, and can be very brutal.
A. careless
B. cruel
C. strong
D. hard【答案】B【解析】句意：Jensen是个危险人物，他可能会很残忍。brutal残忍的；野蛮的；无情的。cruel残酷的，残忍的；无情的。二者意思相近，此处可互相替换，因此选B项。careless粗心的；无忧无虑的；漫不经心的。strong强壮的；强烈的。hard困难的；硬的。
3. You’ll have to sprint if you want to catch the train.
A. jump
B. escape
C. run
D. prepare【答案】C【解析】句意：如果想赶上火车，你必须快点跑。sprint冲刺，全速短跑。run奔跑。二者意思相近，此处可相互替换，因此选C项。jump跳；跳过。escape逃跑。prepare准备。
4. We are worried about this fluid situation filled with uncertainty.
A. changeable
B. stable
C. suitable
D. adaptable【答案】A【解析】句意：对于这个充满不确定的不稳定的情况，我们感到担忧。fluid易变的，不固定的；流动的。changeable易变的；可变的。二者意思相近，此处可相互替换，因此选A项。stable稳定的。suitable合适的，适当的。adaptable可适应的；有适应能力的。
5. The new garment fits her perfectly.
A. haircut
B. purse
C. clothes
D. necklace【答案】C【解析】句意：新衣服很合适她。garment衣服，服装。clothes衣服，衣物。二者意思相近，此处可相互替换，因此选C项。haircut理发；发型；发式。purse钱包。necklace项链。
6. The phobia may have its root in a childhood trauma.
A. fear
B. joy
C. hurt
D. memory【答案】C【解析】句意：恐惧症可能根源于童年受到的精神创伤。trauma创伤（由心理创伤造成精神上的异常）；损伤；痛苦经历。hurt“伤害；痛苦”，可指感情上的伤心或痛苦。二者意思相近，此处可相互替换，因此选C项。fear害怕。joy喜悦，快乐。memory记忆，记忆力。
7. They have to build canals to irrigate the desert.
A. decorate
B. water
C. change
D. visit【答案】B【解析】句意：他们必须修建沟渠灌溉沙漠。irrigate灌溉。water给……浇水。二者意思相近，此处可相互替换，因此选B项。decorate装饰。change改变。visit访问；参观。
8. Her overall language proficiency remains that of a toddler.
A. disabled
B. pupil
C. teenager
D. baby【答案】D【解析】句意：她整体的语言能力还停留在初学的幼儿水平。toddler学步的幼儿。baby婴儿。二者意思相近，此处可相互替换，因此选D项。disabled残废的，有缺陷的。pupil学生。teenager青少年。
9. The coastal area has very mild winter, but the central plains remain extremely cold.
A. warm
B. severe
C. hard
D. dry【答案】A【解析】句意：沿海地区冬天气温温暖，但是中部平原地区却极度寒冷。mild温暖的；温柔的。warm温暖的。二者意思相近，此处可相互替换，因此选A项。severe严峻的，严厉的。hard困难的，硬的。dry干的。
10. The details of the costume were totally authentic.
A. real
B. outstanding
C. creative
D. false【答案】A【解析】句意：这件古装的每个小地方都完全真实。authentic真的，真正的。real真的；真实的。二者意思相近，此处可相互替换，因此选A项。outstanding杰出的；显著的。creative创造性的，有创造力的。false虚伪的；非法的；假造的。
11. We are aware of the potential problems.
A. global
B. possible
C. ongoing
D. central【答案】B【解析】句意：我们意识到了潜在的问题。potential潜在的，有可能的。possible可能的。二者意思相近，此处可相互替换，因此选B项。global全球的。ongoing不间断的，进行的。central中央的，中心的。
12.The idea was quite brilliant.
A. positive
B. clever
C. key
D. original【答案】B【解析】句意：这个主意相当巧妙。brilliant聪明的；杰出的。clever 聪明的，灵巧的。二者意思相近，此处可相互替换，因此选B项。positive积极的；确实的。key关键的。original原始的；最初的。
13. Stock market price tumbled after rumor of a rise in interest rate.
A. regulated
B. increased
C. fell
D. maintained【答案】C【解析】句意：谣传利率上升之后，股票市场价格猛跌。tumble暴跌；倒塌；跌倒。fall下降，落下；倒下。二者意思相近，此处可相互替换，因此选C项。regulate调整；管理；控制。increase增加。maintain维持；维修。
14. The course gives you basic instructions in car maintenance.
A. coaching
B. idea
C. term
D. aspect【答案】A【解析】句意：该课程在汽车维修方面给了我基本的指导。instruction指导，说明。coaching训练，辅导。二者意思相近，此处可相互替换，因此选A项。idea主意，想法。term学期；术语。aspect方面。
15. All houses within 100 metres of the seas are at risk of flooding.
A. in danger
B. out of control
C. between equals
D. in particular【答案】A【解析】句意：距海100米内的所有房屋都有遭受洪水泛滥的危险。at the risk of处于风险中，冒着……的危险。in danger of处于危险中，有……的危险。二者意思相近，此处可相互替换，因此选A项。out of control失去控制。in particular尤其，特别。
第2部分：阅读判断（第16～22题，每题l分，共7分）
下面的短文后列出了7个句子，请根据短文的内容对每个句子做出判断：如果该句提供的是正确信息，请选择A；如果该句提供的是错误信息，请选择B；如果该句的信息文中没有提及，请选择C。
The Greatest of Victorian Engineers
In the hundred years up to 1860, the work of a small group of construction engineers carried forward the enormous social and economic change that we associate with the Industrial Revolution in Britain. The most important of these engineers was Isambard Kingdom Brunel, whose work in shipping, bridge-building, and railway construction, to name just three fields, both challenged and motivated his colleagues. He was the driving force behind a number of the hugely ambitious projects, some of which resulted in works which are still in use today.
The son of an engineer, Brunel apprenticed with his father at an early age on the building of the Thames Tunnel. At the age of just twenty, he became engineer in charge of the project. This impressive plan to bore under the Thames twice suffered two major disasters when the river broke through into the tunnel when the second breach(决口) occurred in 1872, Brunel was seriously injured during rescue operation and further work was halted.
While recovering from his injuries, Brunel entered a design competition for a new bridge over the Avon Gorge near Clifton. The original judge of the competition was Thomas Telford, a leading civil engineer of his day, who rejected all entries to the competition in favor of his own design. After considerable scandal, a second contest was held and Brunel's design was accepted. For reasons of funding, however, exacerbated (加剧) by social unrest in Bristol, the project was abandoned in 1843 with only the towers completed. After Brunel’s death, it was decided to begin work on it again, partly so that the bridge could form a fitting memorial to the great engineer. The entire structure was finally completed in 1864. Today, the well-known Clifton Suspension Bridge is a symbol of Bristol, just as the Opera House is of Sydney. Originally intended only for horse-drawn traffic, the bridge now bears over four million motor vehicles a year.
16. Brunel was an important airplane engineer in Britain during the Industrial Revolution.
A. Right
B. Wrong
C. Not mentioned
17. Brunel was involved less in railway construction than in other engineering fields.
A. Right
B. Wrong
C. Not mentioned
18. Brunel worked only on shipping, bridge-building and railway construction.
A. Right
B. Wrong
C. Not mentioned
19. Brunel work was largely ignored by his colleagues.
A. Right
B. Wrong
C. Not mentioned
20. Some projects Brunel contributed to are still in use today.
A. Right
B. Wrong
C. Not mentioned
21. Brunel became an apprentice with his father when he was very young.
A. Right
B. Wrong
C. Not mentioned
22. The Thames Tunnel project was more difficult than any previous projects undertaken in Britain.
A. Right
B. Wrong
C. Not mentioned【答案与解析】
16.C 点睛：文章第一段对Brunel进行了简单的介绍，第一段第二句提到了“Isambard Kingdom Brunel, whose work in shipping, bridge-building, and railway construction”但是并没有提及他是否是飞机领域的工程师，因此选C项。
17.C 点睛：第一段第二句提到了Brunel是铁道建筑方面的工程师，但是并没有进行各领域之间的对比，因此选C项。
18.B 定位：根据关键词shipping、bridge-building 和railway construction定位到第一段第二句。
点睛：根据第一段第二句中的“to name just three fields”可知，除了文章所列举出来的，Brunel应该还涉及其他工程领域，因此本题选B项。
19.B 点睛：根据第一段第二句“Isambard Kingdom Brunel, whose work…both challenged and motivated his colleagues”可知，题干与原文表述不符，因此选B项。
20.A 定位：根据关键词in use today定位至第一段最后一句。
点睛：根据第一段最后一句“He was the driving force behind a number of the hugely ambitious projects, some of which resulted in works are still in use today.”可知，Brunel推动了许多项目的进行，而且有一些工程建筑仍然在使用，因此本题选A项。
21.A 定位：根据关键词an apprentice和his father定位到第二段第一句。
点睛：根据第二段第一句中的“Brunel apprenticed with his father at an early age”可知，Brunel年轻时候就师从自己的父亲学习工程，因此选A项。
22.C 点睛：文章第二段提到了Thames Tunnel工程。文章中并未涉及Thames Tunnel工程与其他工程项目的对比，因此本题选C项。
第3部分：概括大意和完成句子（第23～30题，每题l分，共8分）
下面的短文后有2项测试任务：（1）第23～26题要求从所给的6个选项中为第1～4段每段选择1个最佳标题；（2）第27～30题要求从所给的6个选项中为每个句子确定1个最佳选项。
Geothermal (地热) Energy
1. Since heat naturally moves from hotter regions to cooler ones, the heat from the earth's center flows outwards towards the surface. In this way, it transfers to the next layer of rock. If the temperature is high enough, some of this rock melts and forms magma (岩浆). The magma ascends in its turn towards the earth's surface. It often remains well below the earth's surface, creating vast areas of hot rock. In such regions, there are deep cracks, which allow rainwater to descend underground. Some of the heated rainwater travels back up to the earth's surface where it will appear as a hot spring. However, if this ascending hot water reaches a layer of impermeable (不可渗透的) rock, it remains trapped, forming a geothermal reservoir. If geothermal reservoirs are close enough to the surface, they can be reached by drilling wells. Hot water and steam shoot up the wells naturally, and can be used to produce electricity in geothermal power plants.
2. A few geothermal power plants depend on dry-steam reservoirs which produce steam but little or no water. In these cases, the steam is piped up directly to provide the power to spin a turbine generator. The first geothermal power plant, constructed at Lardarello in Italy, was of this type, and is still producing electricity today.
3. Most currently operating geothermal power plants are either “flash” steam plants or binary (双重的) plants. Flash plants produce mainly hot water ranging in temperature from 300° to 700° Fahrenheit. This water is passed through one or two separators where released from the pressure of the underground reservoir, it “flashes” or boils into steam. Again, the force of this steam provides the energy to spin the turbine and produce electricity. The geothermal water and steam are then reinjected directly back down into the earth to maintain the volume and pressure of the reservoir. Gradually they will be reheated and can then be used again.
4. A reservoir with temperatures below 300° Fahrenheit is not hot enough to flash steam but it can still be used to generate electricity in a binary fluid. The steam from this is used to power the turbines. As in the flash steam plant, the geothermal water is recycled back into the reservoir.
23.Paragraph 1 _____
24.Paragraph 2 _____
25.Paragraph 3 _____
26.Paragraph 4 _____
27. A geothermal reservoir is formed when hot water is trapped under _____.
28. A dry-steam reservoir produces steam with _____.
29. Flash plants produce hot water through _____.
30. In a binary plant, the heat of the geothermal water can be converted into _____.【答案与解析】
23.E 本段主要介绍地热能的产生过程，是由雨水流到地下，遇地热变成热水无法喷出而形成的。E项“地热能的起源”与本段意思相符，故选E项。
24.F 本段主要介绍利用干蒸汽发电的工厂。F项“干蒸汽发电厂”与本段意思相符，故选F项。
25.C 本段主要介绍注水蒸汽发电站，现今最常见的就是注水发电和双循环发电。C项“注水蒸汽发电站”与本段意思相符，故选C项。
26.B 本段主要介绍低于300华氏度的水库如何通过双循环发电站来发电。B项“双循环发电站”能很好地概括本段内容，故选B项。
27.B 定位：根据关键词trapped可定位至第一段倒数第三句。
点睛：文章第一段倒数第三句提到，如果向上的热水碰到不可渗透的岩石，就会被困住，形成地热水库。B项impermeable rock“不可渗透的岩石”与该句意思相符，故选B项。
28.C 定位：根据题干定位至第二段第一句。
点睛：文章第二段第一句提到，干蒸汽水库产生的水量很少甚至没有。C项little or no water“很少或没有水”与该句意思相符，故选C项。
29.E 定位：根据题干定位至第三段第三句。
点睛：文章第三段第三句提到，产生的水会通过一到两个分离器。E项one or two separators“一到两个分离器”与该句意思相符，故选E项。
30.F 定位：根据关键词binary可定位至第四段第一、二句话。
点睛：文章第四段第一句提到，温度不够的水可以用在双循环液体中，第二句话提到，这样产生的蒸汽可以推动涡轮。F项the energy to turn a turbine“推动涡轮的能量”与该句意思相符，故选F项。
第4部分：阅读理解（第31～45题，每题3分，共45分） 下面有3篇短文，每篇短文后有5道题。请根据短文内容，为每题确定l个最佳选项。
第一篇 Sports Star Yao Ming
If Yao Ming is not the biggest sports star in the world, he is almost certainly the tallest. At 2.26m, he is the tallest player in the National Basketball Association (NBA) and holds the record as the most towering Olympian ever to compete in the Game.
But what really stands out about the giant center is his celebrity (名气). Few, if any, Chinese athletes are as well-known as Yao Ming around the world. People across the globe are fascinated with Yao, not only for his basketball prowess (杰出的才能) but also for being a symbol of international commerce.
When Yao joined the Houston Rockets as the No. 1 pick in the 2002 NBA draft he was the first international player ever to be selected first. His assets on the court are clear enough—no NBA player of his size has ever possessed his mobility, so he is a handful (难对付的人) for opponents on either end of the court. But what makes Yao invaluable to the Rockets organization is his role as a global citizen and as a bridge to millions of potential basketball fans in China.
When it was announced in February that Yao would miss the rest of the NBA season and possibly the Olympics with a stress fracture (骨折) in his left foot, a collective shudder spread across China. After considerable debate and discussion, Yao opted to get his foot surgically treated in an operation that placed several tiny screws across the bone, to offer his overburdened foot more support. The surgery was a success, and though the estimated four-month recovery period will leave him little time to prepare with Team China,Yao has vowed to be ready for the Beijing Olympics.
Yao wrapped up a 10-day trip to China, where he underwent a series of traditional Chinese medicine (TCM) treatments, hoping to accelerate his recovery process. Western experts are generally skeptical of TCM’s benefits, although new research from the University of Rochester suggests that a certain compound derived from shellfish may indeed stimulate bone repair.
“There is no reason to dismiss TCM,” Yao told a press conference in Beijing. “It’s been used in our country for thousands of years. I don’t think that it’s short on science.”
31. The word “towering” in Paragraph 1 means _____.
A. large
B. fat
C. tall
D. great
32. Opponents find it very difficult to control Yao Ming because of his _____.
A. assault
B. mobility
C. defense
D. celebrity
33. Yao Ming had to undergo a series of TCM treatments because _____.
A. he wanted to make a more rapid recovery
B. his right foot had been hurting
C. the surgical operation had been a failure
D. he couldn't afford all the medical expenses
34. Which statement about Yao Ming is NOT true?
A. He is an NBA player.
B. He fractured his left foot.
C. He missed the Athens Olympics.
D. He is an international figure.
35. In general, the Western experts’ attitude towards TCM is _____.
A. indifferent
B. positive
C. doubtful
D. negative【答案与解析】
31.C 点睛：文章第一段第一句提到了姚明是最高的。因此第二句中“towering”应该继续指姚明在身高方面的记录，因此本题选C项。towering耸立的；高大的。
32.B 定位：根据关键词opponents和difficult to control定位到第三段第二句。
点睛：根据第三段第二句中的“no NBA player of his size has ever possessed his mobility”，可知，由于姚明身材高大且移动迅速，他很难对付。因此本题选B项。
避错：文章第二段提到了姚明的名气，但是这并不是他很难对付的原因，因此D项不符合题意。A项和C项文中没有提及，因此排除。
33.A 定位：根据关键词a series of TCM treatment定位到最后两段。
点睛：根据倒数第二段第一句中的“hoping to accelerate his recovery process”可知，姚明之所以接受中医药治疗是为了快速恢复，因此本题选A项。
避错：文章第四段只提到了他的左脚受伤，并且提到了手术成功了，因此B项和C项明显错误。D项文中没有提及，因此排除。
34.C 点睛：文章第一段第二句就介绍了姚明是NBA中最高的一名球员，因此A项表述正确。根据文章第二段可知，姚明名气大，是国际商务的一个象征，因此D项与原文表述相符。文章第四段第一句提到了姚明左脚骨折，因此B项表述正确。第四段只提到姚明有可能错过奥运会，并且根据第四段最后一句可知，这里指的是北京奥运会，因此C项表述明显错误。因此本题选C项。
35.C 定位：根据关键词western experts’ attitude和TCM定位到最后两段。
点睛：根据倒数第二段最后一句可知，“Western experts are generally skeptical of TCM’s benefits”，skeptical意思为“怀疑的”，因此本题选C项。【全文翻译】
体育明星姚明
如果姚明不是世界上最大的体育明星，那他几乎肯定是最高的。身高2.26米，他是美国国家篮球协会（NBA）最高的球员，并且是参加奥林匹克比赛的选手中最高身高的记录保持者。
但是这位巨人真正突出的是他的名气。很少有中国运动员，如果有的话，和姚明一样在全世界有名。全球的人们都对姚明着迷，不仅是因为他的篮球技术杰出，也因为他是国际商务的一个象征。
当姚明在2002年NBA选秀中作为状元加入休斯敦火箭队时，他是第一个被选为状元的国际球员。他在场上的价值显而易见——没有NBA球员像他一样身材高大却移动迅速，所以整个篮球场上攻防两端他都是一个难以对付的对手。但是姚明对火箭队不可估量的作用在于他作为全球公民的角色，以及他成为一座桥梁，连接着数百万的潜在中国篮球迷和一座连接着数百万潜在的中国篮球迷的桥梁的角色。
在2月份，当宣布姚明由于左脚压力骨折而将错过NBA剩下的赛季，而且还有可能错过奥林匹克时，整个中国无不震惊。在大量的辩论和讨论后，姚明选择在脚上动一个手术，放置几个小螺丝穿过骨头，从而给他不堪重负的脚更多的支撑。手术是成功的，虽然预计的四个月的恢复期给他留下不多的时间来与中国队磨合，姚明已经誓言要为北京奥运会做好准备。
姚明结束了一个为期10天的中国之行，在那里他接受了一系列的中医药治疗，希望能加速他的康复过程。西方专家普遍对中药的益处表示怀疑，尽管罗切斯特大学的新研究表明，某些来自贝壳类的化合物确实能刺激骨修复。“没有理由不用中医药，”姚明在北京的一个新闻发布会上说。“在我们国家中医药已经有几千年的历史了。我认为它并不缺乏科学。”
第二篇 Deforestation and Desertification (沙漠化)
The Sahel zone lies between the Sahara desert and the fertile savannahs (热带大草原) of northern Nigeria and South Sudan. The word sahel comes from Arabic and means marginal or transitional, and this is a good description of these semi-arid (半干旱) lands, which occupy much of the Western African countries of Mali, Mauritania, Niger, and Chad.
Unfortunately, over the last century the Sahara desert has steadily crept southwards eating into once productive Sahel lands. United Nations surveys show that over 70 percent of the dry land in agriculture use in Africa has deteriorated over the last 30 years. Droughts have become more severe, the most recent lasting over twenty years in parts of the Sahel region. The same process of desertification is taking place across southern Africa as the Kalahari desert advances into Botswana and parts of South Africa.
One of the major causes of this desert advance is poor agricultural land use, driven by the pressures of increasing population. Overgrazing—keeping too many farm animals on the land—means that grasses and other plants cannot recover, and scarce water supplies are exhausted. Over cultivation—trying to grow too many crops on poor land—results in the soil becoming even less fertile and drier, and beginning to break up. Soil erosion (侵蚀) follows, and the land turns into desert.
Another cause of desertification is loss of tree cover. Trees are cut down for use as fuel and to clear land for agricultural use. Tree roots help to bind the soil together, to conserve moisture, and to provide a habitat for other plants and animals. When trees are cut down, the soil begins to dry and loosen, wind and rain erosion increase, other plant species die, and eventually the fertile top soil may be almost entirely lost, leaving only bare rock and dust.
The effects of loss of topsoil and increased drought are irreversible. They are, however, preventable. Careful conservation of tree cover and sustainable agricultural land use have been shown to halt deterioration of soils and lessen the effects of shortage of rainfall. One project in Kita in south-west Mali funded by UNDP has involved local communities in sustainable management of forest, while at the same time providing a viable (有活力的) agricultural economy. This may be a model for similar projects in other West African countries.
36.The Sahel zone is an area which ___.
A. is covered with sand and grass
B. has a long history
C. occupies much of South Nigeria
D. belongs to Sudan
37. What is the situation about the desertification in Africa?
A. The deserts are replaced with grasslands.
B. The deserts are expanding.
C. The deserts are moving northwards.
D. The deserts are being deserted.
38. The word “deteriorated” in paragraph 2 means _____.
A. deepened
B. suffered
C. slipped
D. worsened
39. What is the root cause of desertification?
A. Poor farming.
B. Overpopulation.
C. Radical climate change.
D. Disappearance of rare plant species.
40. In order to prevent desertification, the author proposes ___.
A. making good use of international aids
B. developing a sustainable agricultural economy
C. gaining international support
D. converting agricultural land into forest【答案与解析】
36.A 点睛：根据第一段可知，萨赫勒地区位于撒哈拉沙漠和肥沃的热带大草原之间，为半干旱的土地，由此可知，该地区既有沙漠也有草原，属于沙漠和草原过度的地带。
避错：根据第一段第一句可知，萨赫勒地区位于尼日利亚及苏丹之间，C项和D项错误。B项文中没有提及，因此排除。
37.B 点睛：文章第二段的第一句就提到了撒哈拉沙漠在向南扩张（the Sahara desert has steadily crept southwards eating into…），由此可知，B项正确。
避错：文章提到撒哈拉沙漠在向南扩张，因此A、C项错误。D项没有提及，因此排除。
38.D 点睛：第二段第一句首先提到了撒哈拉沙漠在向南扩张，由此可知，第二句中应该是指农业用地恶化，因此本题选择D项。
39.A 点睛：第三段第一句指出“One of the major causes of this desert advance is poor agricultural land use”，由此可知，A项正确。
避错：文章第三段第一句提到了“poor agricultural land use, driven by the pressures of increasing population”，由此可知，人口过多是沙漠化的间接原因，因此B项不符合题意。C项和D项文中没有提及，因此排除。
40.B 定位：根据关键词prvent desertification定位到最后一段。
点睛：根据最后一段第三句可知，小心保护树木、可持续地使用农业用地已被证明能阻止土壤恶化、减缓降雨缺少的影响。因此本题选B项。
避错：文章最后一段提到了联合国开发计划署的资助项目，但是这并不是作者提倡的阻止沙漠化的方法，而是给出一个具体的例证，因此A项和C项不符合题意。D项文中没有提及，因此排除。
第三篇 Older Volcanic Eruptions
Volcanoes were more destructive in ancient history, not because they were bigger, but because the carbon dioxide (二氧化碳) they released wiped out life with greater ease.
Paul Wignall from the University of Leeds was investigating the link between volcanic eruptions and mass extinctions. Not all volcanic eruptions killed off large numbers of animals, but all the mass extinctions over the past 300 million years coincided with huge formations of volcanic rock. To his surprise, the older the massive volcanic eruptions were, the more damage they seemed to do. He calculated the “killing efficiency” for these volcanoes by comparing the proportion of life they killed off with the volume of lava (熔岩) that they produced. He found that size for size, older eruptions were at least 10 times as effective at wiping out life as their more recent rivals.
The Permian (二叠纪) extinction, for example, which happened 250 million years ago, is marked by floods of volcanic rock in Siberia that cover an area roughly the size of western Europe. Those volcanoes are thought to have pumped out about 10 gigatonnes (十亿吨) of carbon as carbon dioxide. The global warming 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 60 million years ago, there was another huge amount of volcanic activity and global warming but no mass extinction. Some animals did disappear but things returned to normal within tens of thousands of years. “The most
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