Part Ⅱ Reading Comprehension(35 minutes)
Passage OneQuestions 21 to 25 are based on the following passage:

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  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 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.

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) Analyzing¹ 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 utilize² 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) Pessimism³.　　　　　B) Hopeful. C) Indifferent. 　D) Doubtful.

内容概要: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。