2020年职称英语理工A真题：阅读理解(文字版)

1、2020 年职称英语理工 A 真题：阅读理解 ( 文字版)以下试题为网友提供，仅供考生参考 ! Older Volcanic EruptionsVolcanoes were more destructive in ancient history, not because they were bigger, but because the carbon dioxide they released wiped out life with greater ease.Paul Wignall from the University of Leeds was investigating the link

2、 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 massivevolcanic eruptions were, the more dama

3、ge they seemed to do. He calculated the "killing efficiency" for these volcanoes by comparing the proportion of life they killed off with thevolume of lava 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

4、recent rivals.The Permian 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 of carbon as carbon dioxide. The global wa

5、rming that followed wiped out 80 per cent of all marine genera at the time, and it took 5 million years for the planet torecover. 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 ton

6、ormal within ten thousands of years. "The most recent ones hardly have an effect at all," Wignall says. He ignored the extinction which wiped out the dinosaurs 65 million years ago, because many scientists believe it was primarily caused by the impact of an asteroid. He thinks that older v

7、olcanoes had more killing power because more recent life forms were better adapted to dealing with increased levels of CO2.Vincent Courtillot, director of the Paris Geophysical.Institute in France, says that Wignalls idea is provocative.But he says it is incredibly hard to do these sorts of calculat

8、ions. He points out that the killing power ofvolcanic eruptions depends on how long they lasted. And it is impossible to tell whether the huge blasts lasted for thousands or millions of years. He also adds that it isdifficult to estimate how much lava prehistoric volcanoes produced, and that lava vo

9、lume may not necessarily correspond to carbon dioxide emissions.Black Holes TriggerScientists have long understood that supermassive black holes weighing millions or billions of suns can tear apartstars that come too close.The black hotels gravity pullsharder on the nearest part of the star， an imba

10、lance thatpulls the star apart over a period of minutes or hours，once it gets close enough.Scientists say this Uneven pulling is not the only hazard facing the star.The strain of these unbalanced forces can also trigger a nuclear explosion powerful enough to destroy the star from within.Matthieu Bra

11、ssart and Jean-PierreLuminet of the Observatoire de Paris in Meudon， France1，carried out computer simulations of the final moments of such an unfortunate stars life， as it veered towards a supermassive black hole.When the star gets close enough， the uneven forces flatten it into a pancake shape.Some

12、 previous studies had suggested this flattening would increase the density and temperature inside the star enough to trigger intense nuclear reactions that would tear it apart.But other studies had suggested that the picture would be complicated by shock waves generated during the flattening process

13、 and that no nuclear explosion should occur.The new simulations investigated the effects of shock waves in detail，and found that even when their effects areincluded ， the conditions favor a nuclear explosion. “Therewill be an explosion of the star it will be completely destroyed ，” Brassart says. Al

14、though the explosionobliterates the star，it saves some of the stars matterfrom being devoured by the black hole.The explosion ispowerful enough to hurl much of the stars matter out of the black holes reach ， he says.The devouring of stars by black holes may already have been observed ， although at a much later stage.It is thoughtthat several months after the event that rips the star apart，its matter starts swirling into the hole itself.It heats up as it does so， releasing ultraviolet