英语6级阅读四篇

Scientists say there has been a severe decrease in the amount of water in Lake Chad in northern Africa in the last thirty years. They report that nature and humans share equal blame for this loss.

In 1963 the fresh water lake covered twenty-five-thousand-square kilometers. Now the lake is only about five percent of that size. It measures only about one-thousand-three-hundred square kilometers in the dry season.

Four nations surround Lake Chad. People in Niger, Nigeria, Chad, and Cameroon use it for water, fish and plant life.

Michael Coe and Jonathan Foley are water experts at the University of Wisconsin in Madison. They reported about Lake Chad in the Journal of Geophysical Research. They say the area has suffered from a lack of heavy rain for more than thirty years. This has forced people to build systems to carry water to dry land. These irrigation systems further decrease the lake.

Mister Coe says Lake Chad will be only a small body of water in the future. He says people still can get water from the lake to drink and for crops. But he says the lake will no longer provide a healthy environment for fish and plant life.

The researchers used a computer to study what caused the water loss. Their computer study estimated the climate and amount of water in the area. The estimate started with the early 1960s. Then the researchers compared the estimates with the area's recorded climate and water supply for the same period.

The computer study showed results similar to the recorded ones for the first twenty years. But there was a big change in the 1980s. At that time, the lake got smaller much faster than the computer research had estimated.

The researchers say major irrigation systems were built in the 1980s. The systems took water from two rivers that flow into Lake Chad. The Chari and Logon rivers carry most of the water that enters the lake. The study showed the increased irrigation reduced the flow in the two rivers. Climate changes also were responsible for the reduction. Today the flow of the two rivers has been reduced by almost seventy-five percent.

Scientists say the problem is expected to worsen in the coming years as the population and demand for water continue to increase.

21.What is this passage mainly about?

A) Demonstrating the serious weather condition around Lake Chad.

B) Introducing people's activity around Lake Chad.

C) Analyzing of the factors that cause water decreases in Lake Chad.

D) Introducing scientists' work about water condition in Lake Chad.

22.What did people do to solve the problem of rain lack around Chad Lake?

A) They moved out of this area.

B) They drew water from Lake Chad.

C) They carried water from other areas.

D) They utilize seawater near this area.

23.Which of the following is true according to this passage?

A) Chad Lake located in the middle of Chad in northern Africa.

B) The water from Chad water can now only be used for irrigation.

C) The area around Chad Lake has suffered from heavy rain lack many decades.

D) Population around the Chad Lake now begins to decrease due to water lack.

24.Why computer data become imprecise in 1980s?

A) The related programs on the computer were out of date.

B) More and more people drew water directly from the lake for drink.

C) A heavy rain happened around 1980.

D) The irrigation from the source water increases.

25. What is scientists' attitude towards the future of Chad Lake?

A) Pessimism. B) Hopeful. C) Indifferent. D) Doubtful.

本文分析了北非乍得湖严重干枯的原因。这里既有自然因素，如缺乏降雨；也有人为因素，如抽水灌溉现象过于严重以及对水源的截取过多等.最后引用科学家的预测说乍得湖的情况将进一步恶化下去。

21.【答案】C。

【译文】本文分析导致乍得湖干枯的原因。

【试题分析】主题题。

【详细解答】A)只是文中提及的自然因素；文中提及people's activity只是为了说明人为因素; 介绍科学家的工作也是为了分析原因。因此A),B),D)均为错误答案。

22.【答案】B。

【译文】生活在乍得湖区域的人们建造灌溉系统从湖中抽取水分来解决长期干旱问题。

【试题分析】细节推理题。

【详细解答】关键段落:\" This has forced people to build systems to carry water to dry land. These irrigation systems further decrease the lake.\"可见人们采取的方式是从湖中提取水分。而A)迁移出去;C)从其他地方运水;D)从海水中运水文中均未提及。

23.【答案】C。

【译文】乍得湖区域缺乏降雨的处境已持续几十年了。

【试题分析】客观事实题。

【详细解答】关键语句：\"They say the area has suffered from a lack of heavy rain for more than thirty years. \"因此C)选项正确。而因文中\"Four nations surround Lake Chad.\" A)错误; \"He says people still can get water from the lake to drink and for crops.\" B)错误; \"Scientists say the problem is expected to worsen in the coming years as the population and demand for water continue to increase.\" D)错误。

24.【答案】D。

【译文】由于湖区的水源被抽取过多导致计算机数据在八十年代与实际不符。

【试题分析】客观事实题。

【详细解答】关键语句：\"The researchers say major irrigation systems were built in the Nineteen-Eighties. The systems took water from two rivers that flow into Lake Chad. The Chari and Logone rivers carry most of the water that enters the lake. The study showed the increased irrigation reduced the flow in the two rivers. Climate changes also were responsible for the reduction. Today the flow of the two rivers has been reduced by almost seventy-five percent.\"可见一方面是湖区水源抽取过多,另一方面是天气情况变得恶劣，D)正确。A), C)在文中均未提及。B)不应是directly,且用于drink也不妥当。

25.【答案】A。

【译文】科学家对乍得湖区的前景持不乐观态度。

【试题分析】态度判断题。【详细解答】关键语句: \"Scientists say the problem is expected to worsen in the coming years as the population and demand for water continue to increase.\"且从贯穿全文的语气可以看出不抱乐观态度。

Scientists have long believed one way to stop the Earth's atmosphere from warming is by planting more trees. The idea is that more trees will take in or absorb some of the carbon dioxide in the atmosphere. Carbon dioxide is a gas released by cars, factories and other human activities. The gas traps heat in the Earth's atmosphere, which warms the planet. However, two new studies have found that trees may not be as helpful in reducing carbon dioxide as had been thought.

The first study was done at Duke University in Durham, North Carolina. Researchers pumped extra carbon dioxide into a test area where pine trees were growing. The trees grew thirty-four percent faster during the first three years. However, in time, the trees slowed to about their normal growth rate. The scientists say this is because trees need other nutrients, such as nitrogen.

In the second study, researchers from Duke and Bowdoin College in Brunswick, Maine examined the soil around trees. They discovered that as the leaves broke down into the soil, all the carbon was not trapped in the soil. Much of it was released into the atmosphere as carbon dioxide.

The findings of the two studies were published last month in Nature magazine. They suggest there is limited value in planting trees to reduce the carbon dioxide pollution in the atmosphere.

Forest planting has been a part of negotiations on a world agreement to reduce greenhouse gases that scientists believe cause global warming. The United States, Canada, Japan and some other industrial countries have supported the idea. But this new research suggests the idea is not as effective as environmental activists had thought. Scientist Ram Oren of Duke University led the study on tree growth. He says that earlier estimates on the ability of forests to absorb carbon dioxide were overly hopeful.

Some scientists not involved in the studies say the research provides some of the first evidence on how trees react to carbon dioxide. Other scientists say the

research disputes a belief among some coal and power companies. The companies say that rising levels of carbon dioxide in the atmosphere will not create harmful global warming. Instead, they say it will increase forests and other plants.

26.What is the purpose of this passage?

A) Introduce some new ideas about the relationship between trees and carbon dioxide.

B) Introduce recent condition of global industrial pollution.

C) Call on people to plant more trees to reduce greenhouse gases.

D) Point out that power companies should be responsible for the rising levels of carbon dioxide.

27. Why researchers put trees in extra carbon dioxide in the first study?

A) To learn whether trees can still absorb carbon dioxide under extreme conditions.

B) To get more oxygen from these trees.

C) To evaluate the maximum carbon dioxide that trees can absorb.

D) To see the growth rate of these trees.

28. What happened to the leaves falling from the trees in the second study?

A) They broke down and the main parts turned into oxygen.

B) They broke down and the carbon content had mainly turned into carbon dioxide.soil.

C)They broke down and the carbon content was mainly absorbed in the

D) They absorbed more carbon dioxide.

29. Scientist Ram Oren is of the opinion that common beliefs of the tree's ability to absorb carbon dioxide are____.

A) biased B) insightful

C) overoptimistic D) totally wrong

30.The word \"it\" (Line 7, Para.6) probably refers to ____.

A) carbon dioxide B) nitrogen

C) atmosphere D) coalPassage Two

内容概要:

本文介绍了树林与二氧化碳关系的新学说。一些科学家为此做了实验，结果证明树木对二氧化碳的吸收作用并没有人们想象的那么乐观，据此指出现在的一些做法与观点是错误的。

26.【答案】A。

【译文】本文主要介绍了一些科学家提出的关于树林与二氧化碳关系的新学说。

【试题分析】主题题。

【详细解答】B),D)均与本文无关；C)则由于实验显示树木吸收并不那么有效，因此从本文观点来看正好错误。

27.【答案】D。

【译文】研究者把树木放入过量二氧化碳的环境中研究树木相应的生长规律。

【试题分析】细节推理题。

【详细解答】关键语句：\"The trees grew thirty-four percent faster during the first three years. However, in time, the trees slowed to about their normal growth rate. The scientists say this is because trees need other nutrients, such as nitrogen.\"可以看出是研究生长规律.A),B),C)均和本文无关。

28.【答案】B。

【译文】在第二个试验中落下的树叶分解后,包含的主要碳成分转化为二氧化碳。

【试题分析】客观事实题。

【详细解答】关键语句：\"They discovered that as the leaves broke down into the soil, all the carbon was not trapped in the soil. Much of it was released into the atmosphere as carbon dioxide.\" 而A), C), D) 均错误。

29.【答案】C。

【译文】科学家Ram Oren认为大众对树叶作用的观点过于乐观。

【试题分析】态度判断题。

【详细解答】关键语句：\"He says that earlier estimates on the ability of forests to absorb carbon dioxide were overly hopeful.\"可见他认为普通观点过于乐观。

30.【答案】A。

【译文】对应段落里的 \"it\" 指二氧化碳。

【试题分析】词意判断题。

【详细解答】关键语句：\"The companies say that rising levels of carbon dioxide in the atmosphere will not create harmful global warming. Instead, they say it will increase forests and other plants.\" 可见应是二氧化碳.其余选项与本段无关。

Passage Three

Questions 31 to 35 are based on the following passage:

An American scientist has found that many images of dinosaurs may be wrong. For years, pictures of the ancient creatures have shown their nose openings near the top of the head. The new study suggests the dinosaurs' nostrils were just above the mouth.

Dinosaurs used their nostrils to breathe, smell and control their body temperature. The new theory could help explain how the huge creatures were able to survive by using their sense of smell to find food, a mate and possible enemies.

Lawrence Witmer of Ohio University in Athens, Ohio led the study. The publication science reported his findings.

Many of the early dinosaur remains recovered by scientists were from huge creatures called sourwoods. Scientists believed that sourwoods must have lived in water because their bodies were so huge and their necks were so long.

Nostrils high on the head would have permitted the dinosaurs to breathe while partly under water. The discovery of a sauropod head bone in 1884 added support for this belief. The skull had a large hole at the top of the head.

Professor Witmer says experts learned years later that sauropods generally were not sea creatures. But he says the earlier theory about nostril position was extended to other dinosaurs.

Only dinosaur bones have survived as fossil remains. Scientists have never recovered dinosaur remains of soft tissue. Scientists interested in the physical appearance of dinosaurs often study birds and animals similar to the ancient creatures. Professor Witmer examined forty-five kinds of birds, crocodiles and lizards that are the closest living relatives to dinosaurs. He noted the placement of soft tissue through hundreds of x-ray images and by cutting pieces of tissue. Soft tissue leaves markings on bone. Professor Witmer used this information to make a map of the likely position of soft tissue in the dinosaurs' noses. He found that the birds and reptiles he studied share a common nostril position.

Professor Witmer found that the hole scientists once thought was a nostril in dinosaurs is just one part of the larger nasal passage. He found that the nostrils were farther forward and closer to the mouth. He says this new nostril position was true for all dinosaurs.

31. Where is this article likely to be excerpted from?

A) Biology textbook. B) Scientific report.

C) Science fiction. D) Essay.

32. One advantage with Nostrils high on the head is to ____.

A) use sense of smell more efficiently

B) help them move fast and alert

C) enable them to find more food

D) help them live under water more easily

33.Which of the following may not be a reason why Professor Witmer studies crocodiles and lizards in his experiments?

A) They are close relatives to dinosaurs.

B) Their soft tissues survive as fossil remains.

C) Their soft tissues have similar traits with dinosaurs.

D) He cannot find living dinosaurs.

34.What does \"this information\" (in paragraph 7) refer to?

A) Soft tissues. B) Bone.

C) Markings. D) Nose.

35.The word \"passage\" (Line 2, Para.8) means____.

A) gate B) channel

C) cross D) paragraph

Passage Three

内容概要:

本篇文章报道了一个新的科学观点,即恐龙鼻孔应紧贴嘴巴上方。文章简要介绍了以前的老观点(认为鼻孔高居头上)，并阐明了新观点的提出人Professor Witmer的研究方法和科研成果。

31.【答案】B。

【译文】本篇文章更像是一篇科学报道的一部分。

【试题分析】题材判别题。

【详细解答】可以看出C)科幻小说D)散文均不可能。而本文更像是一篇关于新发现的报道,因此B)正确。

32.【答案】D。

【译文】鼻孔高居头上可以使恐龙在水下生活的更自在。

【试题分析】细节推理题。

【详细解答】关键语句:\"Nostrils high on the head would have permitted the

dinosaurs to breathe while partly under water.\" B),C)均与文章无关；A)应与新观点有关，可见文中所述\"The new theory could help explain how the huge creatures were able to survive by using their sense of smell to find food, a mate and possible enemies.\"

33.【答案】B。

【译文】Professor Witmer以鳄鱼和蜥蜴为实验研究对象并不是因为它们的软组织可以作为化石幸存下来。

【试题分析】客观事实题。

【详细解答】关键语句:\"Scientists interested in the physical appearance of dinosaurs often study birds and animals similar to the ancient creatures. Professor Witmer examined forty-five kinds of birds, crocodiles and lizards that are the closest living relatives to dinosaurs.\"可以看出A),C)正确，而D)显然正确;B)文中未提。

34.【答案】C。

【译文】句法分析题。

【试题分析】句中的\"信息\"应指代软组织留下的标记。

【详细解答】关键语句\"Soft tissue leaves markings on bone. Professor Witmer used this information to make a map of the likely position of soft tissue in the

dinosaurs' noses.\"可见应指代markings。

35.【答案】B。

【译文】词汇分析题。

【试题分析】\"passage\"应指channel(通道)。

【详细解答】A)gate(门) C)cross(十字路口) D) paragraph(段落)均不符合题意。

Passage Four

Questions 36 to 40 are based on the following passage:

Carbon dioxide makes up less than one percent of the Earth's atmosphere. But the gas is very important to life on Earth. Scientists are finding that processes involving carbon dioxide affect our climate in ways that are difficult to understand. Last month, a committee of the National Academy of Sciences in Washington released a report. It confirmed that world temperatures increased about six-tenths of a degree Celsius in the last one hundred years. The report also confirmed evidence that the level of carbon dioxide is increasing.

The best information about climate in the past comes from tests of ice many kilometers deep in Antarctica and Greenland. The tests show changes in temperature during the past four-hundred-thousand years. These tests show that levels of carbon dioxide today are the highest ever measured. These findings have

led scientists to believe that carbon dioxide is a major cause of climate warming.

Carbon dioxide is released into the atmosphere when fuel is burned. Oil, coal and wood are all fuels that release the gas. When biological waste breaks down, it also releases carbon dioxide.

However, plants use carbon dioxide in the process called photosynthesis. This process provides food for almost all life on Earth. Some groups that support burning oil and coal want to increase the amount of carbon dioxide in the atmosphere. They oppose international efforts to control carbon dioxide.

Some scientists believe that forests and trees are able to capture large amounts of carbon dioxide from the air. Some groups even suggest that an increase in carbon dioxide could cause plants to grow faster.

A recent study in North Carolina found that more carbon dioxide in the air could cause trees to grow faster. But the researchers found the effect appears to last for only three years. Another study showed that much of the carbon dioxide that is taken in by trees is released within three years. The study noted that leaves release carbon dioxide when they fall from trees and break down in the soil. Plants also naturally release carbon dioxide through the process of respiration.

The natural balance of gases in the atmosphere is a complex scientific issue. The debate over carbon dioxide is only one part of efforts to understand world

climate change.

36.Which one is NOT mentioned in this passage that can be the source of carbon dioxide?

A) Oil. B) Trees.

C) Wood. D) Soil.

37.The committee report of National Academy of Sciences in Washington reveal that____.

A) ice from Antarctica and Greenland is appropriate to show the change

B) carbon dioxide is released mainly from the fuel

C) level of carbon dioxide increases with global temperatures

D) carbon dioxide is helpful for tree growth

38.According to this passage, those people disagree with the control of carbon dioxide because____.

A) they think that carbon is beneficial for plant growth

B) they want to use more fuels that can emit carbon dioxide

C) they think carbon dioxide is not the main reason for global warming

D) they think it will destroy the natural balance of gases in the world

39.The word \"issue\" in the last paragraph can be replaced as ____.

A) organ B) topicC) publication D) result

40.Those studies carried out in North Carolina suggest that ____.

A) trees' function for absorbing carbon dioxide is limited

B) carbon dioxide is the main cause for global warming

C) leaves falling from trees can emit more oxygen

D) more carbon dioxide is beneficial for trees' growth for many decades

Passage Four

内容概要:

本文分析了二氧化碳以一些鲜为人知的方式导致气候变化，介绍了科学家所做的相关实验，具体方式，所持的各种观点，最后指出这是一个复杂的问题。

36.【答案】D。

【译文】在本文中土壤未被提及是二氧化碳的源头。

【试题分析】客观事实题。

【详细解答】可见第四段\"Oil, coal and wood are all fuels that release the gas.\"倒数第二段\"The study noted that leaves release carbon dioxide when they fall from trees and break down in the soil. Plants also naturally release carbon dioxide through the process of respiration.\"而土壤未被提及过。

37.【答案】C。

【译文】研究报告表明二氧化碳的浓度随着全球气温升高而增加。

【试题分析】客观事实题。

【详细解答】关键语句:\"The tests show changes in temperature during the past four-hundred-thousand years. These tests show that levels of carbon dioxide today are the highest ever measured.\"可见C)正确.A)是作实验的原料而不是分析结果.B),D)为下面的内容。

38.【答案】B。

【译文】反对控制二氧化碳的这些人目的在于燃烧更多能燃烧二氧化碳的原料。

【试题分析】事实推理题。

【详细解答】关键语句:\"Some groups that support burning oil and coal want to increase the amount of carbon dioxide in the atmosphere. They oppose international efforts to control carbon dioxide.\" C), D)在文中没提.而A)而在文中出现在:\"Some groups even suggest that an increase in carbon dioxide could cause plants to grow faster.\"可见至少不是动机。

39.【答案】B。

【译文】词义判析题。

【试题分析】最后一段的\"issue\"应指Topic。

【详细解答】根据后面的debate也可以看出这是一个科学论题。A)器官，C)刊物，D)结论，均不符合题意。

40.【答案】A。

【译文】事实分析题。

【试题分析】在北卡罗来那州的试验表明树木对二氧化碳的吸收作用是有限的。

【详细解答】关键语句:\"A recent study in North Carolina found that more carbon dioxide in the air could cause trees to grow faster. But the researchers found the effect appears to last for only three years. Another study showed that much of the carbon dioxide that is taken in by trees is released within three years.\"而C)应是放出二氧化碳;D)只有三年;B)是本文开头所做的试验。