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A．Recommending Jane a part-time job.B．Asking more people to help Jane.C．Organizing a p
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A．The teacher should teach his students more about the subject.B．The teacher should af
Section B
Directions: There are 2 passages in this section. Each passage is followed by some questions or unfinished statements. For each of them there are four choices marked A, B, C and D. You should decide on the best choice.
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 low 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.
What is this passage mainly about？
A．The friend was very hungry.B．There are eggs and chicken in the refrigerator.C．He wou
听力原文： Human beings enjoy challenges. Many of them like physical challenges. They ask themselves questions like these: How fast can I run ？ How high can I climb？ How deep can I dive？ How far can I swim？ How long can I hold my breath？ How much can I lift？ How high can I jump？ Because people enjoy challenges, they like to play sports and watch other people play sports. They like climbing, running, diving, lifting, jumping, and so on. Every four years millions of people all over the world enjoy the international sports competitions called the Olympics.
There are challenges that are not physical challenges. There are social and intellectual challenges, too. Leonardo Da Vinci, who lived in Italy during the fifteenth century, enjoyed every possible challenge. He was an artist and painted the well-known picture, the Mona Lisa. He was an inventor who invented a device to let people breathe under water. He was a scientist, and he learned a great deal about human anatomy.
Another kind of challenge faced the Egyptians between 4,000 and 5,000 years ago when they decided to build the first pyramid. They used six million tons of rock. That is enough to build a ten-foot wall around all of France. Four hundred thousand men worked for twenty years to build it.
So, for thousands of years, people accept challenges. Today we still have many challenges before us. Medical science faces the challenges of conquering the many diseases which still attack human beings. Engineers and planners must build new cities and new kinds of transportation. Scientists must develop new forms of energy. And many of us are interested in the challenge of space. We live in an age of challenge.
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