Question

An absolute description of the threat hanging over the world's mammals,reptiles,amphibians and other life forms has been published by the well-known scientific journal,Nature.A special analysis carried out by the journal indicates that an astonishing 41% of all amphibians on the planet now face extinction while 26% of mammal species and 13% of birds are similarly threatened.

Many species are already critically endangered and close to extinction,including the Sumatran elephant,Amur leopard and mountain gorilla.But also in danger of vanishing（消失）for the wild,it now appears,are animals that are currently rated as merely being endangered.

In each case,the finger of blame points directly at human activities.The continuing spread of agriculture is destroying millions of hectares of wild habitats every year,leaving animals without homes,while the introduction of newly-come species,often helped by humans,is also damaging native populations.At the same time,pollution and overfishing are destroying ocean ecosystems.

"Habitat destruction,pollution or overfishing either kill off wild creatures and plants or leaves them badly weakened," said Derek Tittensor,an ocean ecologist at the World Conservation Monitoring Centre in Cambridge. "The trouble is that in coming decades,the additional threat of worsening climate change will become more and more common and could then kill off these survivors."

The problem,according to Nature,is worsened because of the huge gaps in scientists knowledge about the planet's biodiversity.Evaluations of the total number of species of animals and plants alive vary from 2 million to 50 million.In addition,evaluations of current rates of species' disappearances vary from 500 to 36,000 a year. "That is the real problem we face," added Tittensor. "The scale of uncertainty is huge."

In the end,however,the data indicate that the world is heading cruelly towards a mass extinction-which is defined as one involving a loss of 75% of species or more.This could arrive in less than a hundred years or could take a thousand,depending on extinction rates.

1.What's the main idea of the first two paragraphs?

A. Figures about some wild animals are astonishing.

B. Nature is the famous journal around the world.

C. Many endangered species are close to extinction.

D. Some rare species have appeared around the world.

2.From paragraph 4 we know that another future threat is      .

A. destruction of habitats    B. overfishing and pollution

C. the worsening climate change    D. killing off wild creatures and plants

3.What is the real problem we are facing now according to paragraph 5?

A. The killing of wild creatures and cutting of trees.

B. The global warming caused by human beings.

C. The destruction of ocean ecosystem by pollution.

D. Evaluation of current rates of species' disappearances.

4.What does "This" in the last sentence refer to?

A. mass extinction.    B. extinction rates.

C. extinction time.    D. 75% of species or more.

Answer

1.C

2.C

3.D

4.A

【解析】本文讲了世界著名杂志“自然”，做了一个特别的分析，用一些惊人的数据说明世界上的一些动物正面临灭绝。同时指出，造成这些动物灭绝的主要原因是人类的破坏活动。

1.主旨大意题。由第一段的“an astonishing 41% of all amphibians on the planet now face extinction while 26% of mammal species and 13% of birds are similarly threatened.”这个星球上惊人的41%的两栖动物现在面临灭绝，而26%的哺乳动物和13%的鸟类同样受到威胁。第二段中的“Many species are already critically endangered and close to extinction,”许多物种已经濒临灭绝，可知文章前两段主要讲“许多物种濒临灭绝”这样一个事实。故选C。

2.细节理解题。由第四段中的“The trouble is that in coming decades,the additional threat of worsening climate change will become more and more common and could then kill off these survivors.”麻烦的是，在未来几十年，气候恶化将越来越普遍，这将会导致一些幸存下来的物种走向灭绝。可知未来的另一个威胁是气候恶化。故选C。

3.推理判断题。由第五段中的“evaluations of current rates of species' disappearances vary from 500 to 36,000 a year. "That is the real problem we face," added Tittensor. "The scale of uncertainty is huge.”目前动物的消失比率估计在500到36000之间，这才是我们面临的真正问题，即不确定性太大。由此可知，“evaluations of current rates of species' disappearances”物种消失率的评估，是人类面临的真正问题，故选D。

4.词义推测题。由最后一段“In the end,however,the data indicate that the world is heading cruelly towards a mass extinction-which is defined as one involving a loss of 75% of species or more.This could arrive in less than a hundred years or could take a thousand,depending on extinction rates.”总之，数据显示我们的世界正走向一场大灭绝，这场灭绝将导致75%甚至更多的物种灭绝，这在100年之内就会发生。由此可推知，“this”指的是大灭绝。故选A。

【名师点睛】：

主旨要义型题范围一般包括：短文标题、主题大意或段落大意等。

此题型要求考生在理解文章后归纳文章要点，概括中心思想。考生需要分析文章的篇章结构，抓住文章的开头或结尾，从而找出能概括文章的主题句。主题句的特点：(1)语言特点：归纳性、概括性、抽象性；(2)位置特点：主题句常出现在“总结性”语言的“信号词”后，如：in summary, in a word, as a result, finally, in short, in conclusion和in brief等；主题句常出现在“转移话题式”语言的“信号词”后，如：but, however, nevertheless，hence等。例如：本题中的第1小题：

1. What's the main idea of the first two paragraphs?

A. Figures about some wild animals are astonishing.

B. Nature is the famous journal around the world.

C. Many endangered species are close to extinction.

D. Some rare species have appeared around the world.

【解题剖析】该小题属于段落大意。由第一段的“an astonishing 41% of all amphibians on the planet now face extinction while 26% of mammal species and 13% of birds are similarly threatened.”这个星球上惊人的41%的两栖动物现在面临灭绝，而26%的哺乳动物和13%的鸟类同样受到威胁。第二段中的“Many species are already critically endangered and close to extinction,”许多物种已经濒临灭绝，可知文章前两段主要讲“许多物种濒临灭绝”这样一个事实。故选C。