B

It is natural that children are curious about the world around them. For example, they want to know how their hearts beat. They want to know why the ocean water tastes salty.

　　As children grow up, they become curious about different kinds of things. When they are babies, they are interested in the parts of their bodies and in the smiles of their mothers. They become interested in the physical world around them: the plants, the animals, the sky. Later, they become interested in the things that people have made: wheels, bicycles, cars. And when they are adults, their curiosity continues. Sometimes this curiosity leads to a career (生涯、职业) in science.

　　Scientists spend their lives trying to find out about the world．Those who work with the earth sciences study the earth, the oceans, and the skies. Other scientists who study living things work with the biological sciences. A third group of scientists study the physical sciences, e. g. physics, chemistry .

　　These scientists have already discovered a lot about our world．For example, they tell us why your heart beats fast when you run. They say that when you are quiet, your heart normally beats sixty-five or seventy-five times a minute. Your heart is a pump (泵) that pumps blood to all parts of the body. The blood carries oxygen and nutrition. When you run, your muscles work very hard and use the nutrition that the blood carries to them. The muscles need oxygen, too . So your brain sends a signal to the heart. The signal means that the muscles need more nutrition and oxygen. Then the heart beats fast and sends blood quickly to the muscles. It may beat 90 to 140 times a minute.

　　Of course, scientists cannot answer all of our questions. If we ask, “Why does the ocean water taste salty” scientists will say that the salt comes from rocks. When a rock gets very hot or very cold, it cracks. Rain falls into cracks. The rain then carries the salt into the earth and into the rivers. The rivers carry the salt into the ocean. But then we ask , “What happens to the salt in the ocean? The ocean does not get saltier every year.” Scientists are not sure about the answer to this question.

　　We know a lot about our world, but there are still many answers that we do not have, and we are curious.

45．According to the passage, which of the following statements is true?

　  A．People are curious in the same way.

　  B．People in different countries are interested in different things.

　  C．Men and women are curious about different things.

　  D．People of different ages are interested in different things

46．Scientists who work with the biological sciences study____.

A．the earth , the oceans and the sky          B．man-made things

C．plants and animals                               D．ocean water

47．When you run, your muscles need ____.

A．more nutrition and oxygen    B．more signals    C．more salt   D．water

48．A rock cracks _____.

A．in wet regions                                     B．in dry regions

C．at very high or very low temperatures               D．when salty water falls in

B
Scientists have devised a way to determine roughly where a person has lived using a strand (缕) of hair, a technique that could help track the movements of criminal suspects or unidentified murder victims.
The method relies on measuring how chemical variations in drinking water show up in people’s hair.
“You’re what you eat and drink, and that’s recorded in your hair,” said Thure Ceiling, a geologist at the University of Utah.
While U.S. diet is relatively identical, water supplies vary. The differences result from weather patterns. The chemical composition of rainfall changes slightly as rain clouds move.
Most hydrogen and oxygen atoms in water are stable, but traces of both elements are also present as heavier isotopes (同位素). The heaviest rain falls first. As a result, storms that form over the Pacific deliver heavier water to California than to Utah.
Similar patterns exist throughout the U.S. By measuring the proportion of heavier hydrogen and oxygen isotopes along a strand of hair, scientists can construct a geographic timeline. Each inch of hair corresponds to about two months.
Cerling’s team collected tap water samples from 600 cities and constructed a map of the regional differences. They checked the accuracy of the map by testing 200 hair samples collected from 65 barber shops.
They were able to accurately place the hair samples in broad regions roughly corresponding to the movement of rain systems.
“It’s not good for pinpointing (精确定位),” Ceding said. “It’s good for eliminating many possibilities.”
Todd Park, a local detective, said the method has helped him learn more about an unidentified woman whose skeleton was found near Great Salt Lake.
The woman was 5 feet tall. Police recovered 26 bones, a T-shirt and several strands of hair.
When Park heard about the research, he gave the hair samples to the researchers. Chemical testing showed that over the two years before her death, she moved about every two months.
She stayed in the Northwest, although the test could not be more specific than somewhere between eastern Oregon and western Wyoming.
“It’s still a substantial area,” Park said. “But it narrows it way down for me.”
61. According to the passage scientists’ new discovery is that          .
A. One’s hair growth has to do with the amount of water they drink.
B. A person’s hair may reveal where they have lived.
C. Hair analysis accurately identifies criminal suspects.
D. The chemical composition of hair varies from person to person.
62. The underlined sentence “You’re what you eat and drink” (Line 1, Para. 3) means        .
A. Food and drink affect one’s personality development.
B. Food and drink preferences vary with individuals.
C. Food and drink leave traces in one’s body tissues.
D. Food and drink are indispensable to one’s existence.
63. Which of the following is true of the rainfall in America’s West?
A. There is much more rainfall in California than in Utah.
B. The water it delivers becomes lighter when it moves inland.
C. Its chemical composition is less stable than in other areas.
D. It gathers more light isotopes as it moves eastward.
64. Cerling’s team produced__________in their research?
A. a map showing the regional differences of tap water
B. a collection of hair samples from various barber shops
C. a method to measure the amount of water in human hair
D. a chart illustrating the movement of the rain system
65. What is the practical value of Cerling’s research?
A. It helps analyze the quality of water in different regions.
B. It helps the police determine where a crime is committed.
C. It helps the police narrow down possibilities in detective work.
D. It helps identify the drinking habits of the person under investigation.

If you want to improve your child’s results at school, you could do a lot worse than ensuring that they do plenty of exercise. Scientists have already shown that physical activity can make you brainier. But a team in America has used scans to show that an important part of the brain actually grows in children who are fit. These youngsters tend to be more intelligent and have better memories than those who are inactive.

　　Scientists also found that one of the most important parts of their brains was 12 percent larger than those of unfit children. They believe that encouraging children to take exercise from a very young age could help them do better at school later. Researchers from the University of Illinois, in the U.S., studied the brains of 49 children aged nine and ten using a magnetic resonance imaging scan (核磁共振摄影扫描), a technique which provides very detailed pictures of organs and tissues in the body.

　　They also tested the fitness levels of the children by making them run on a treadmill (跑步机). The scientists found that the hippocampus, a part of the brain responsible for memory and learning, was around 12 percent larger in the fitter children.

　　Professor Art Kramer, who led the study published in the journal Brain Research, said the findings had important implications for encouraging individuals to take part in sport from a young age. “We knew that experience and environmental factors and socioeconomic status all impact brain development,” he said. “If you get some terrible genes from your parents, you can’t really fix that, and it’s not easy to do something about your economic status. But here’s something that we can do something about.”

1.If you want to improve your children’s result in school, ____________.

A. it is worse to ensure that they do plenty of exercise

B. you can have their brain scanned

C. it could be better to make sure that they do a lot of exercise

D. you can do a lot except ensuring that they do exercise

2.According to the passage, which of the following statements is NOT true?

A. The fitness level of the children is linked to their intelligence.

B. Children who have a larger hippocampus will probably have better memories.

C. You can do something about the genes from your parents.

D. Unhealthy children will probably have a smaller hippocampus than others.

3. All the following factors that have some influence on one’s brain are mentioned EXCEPT ____________.

A. genetic factor    B. economic status   C. physical fitness  D. economic development

Beijing had its biggest snowfall since 1951. Britain is suffering through its longest cold snap (寒潮) since 1981. And freezing weather is hitting the Deep South, including Florida’s orange groves and beaches.

Whatever happened to global warming?

Such weather doesn’t seem to fit with warnings from scientists that the Earth is warming because of greenhouse gases. But experts say the cold snap doesn’t contradict global warming at all—it’s just a temporary phenomenon in the long-term heating trend. “It’s part of natural variability,” said Gerald Meehl, a senior scientist. With global warming, he said, “we’ll still have record cold temperatures. We’ll just have fewer of them.”

Scientists say man-made climate change does have the potential to cause more frequent and more severe weather extremes. But experts did not connect the current cold snap to climate change.

 So what is going on?

“We basically have seen just a big outbreak of Arctic air over populated areas of the Northern Hemisphere”, Arndt said.

In the atmosphere, large rivers of air travel roughly west to east around the globe between the Arctic and the tropics. This air flow acts like a fence to keep Arctic air restricted. But recently, this air flow has become bent into a zigzag (之字形) pattern, wandering north and south. If you live in a place where it brings air up from the south, you get warm weather. In fact, record highs were reported this week in Washington state and Alaska.

But in the eastern United States, like some other unlucky parts of the globe, Arctic air is coming from the north. And that’s how you get a temperature of 3 degrees in Beijing, a reading of minus-42 in mainland Norway, and 18 inches of snow in parts of Britain. The zigzag pattern arises naturally from time to time, but it is not clear why it’s so strong right now.

1.What is the best title of the text?

A. Freezing weather is hitting the Deep South.

B. We’ll still have record cold temperatures.

C. The air flow has become a zigzag pattern.

D. Cold snap doesn’t contradict global warming.

2.With global warming, we will ______.

A. also meet with severe cold snap

B. have more hot temperatures forever

C. never experience cold temperatures

D. have more cold temperatures

3.According to experts, the current cold snap ______.

A. suggests that the climate has changed greatly

B. is not related to the climate change

C. shows that the climate will turn cold

D. is affected by global warming

4.Beijing had its biggest snowfall since 1951 because of ______.

A. a fence from the Arctic                   B. a cooling trend in climate

C. a big outbreak of Arctic air              D. its large population

5.We can conclude that ______.

A. not all the parts of the Northern Hemisphere are cold in face of the cold snap

B. the zigzag pattern arises naturally accidentally

C. Beijing will get cold weather next year

D. Washington state and Alaska will not face cold weather next year

People diet to look more attractive. Fish diet to avoid being beaten up, thrown out of their social group, and getting eaten as a result. That is the fascinating conclusion of the latest research into fish behavior by a team of Australian scientists.

The research team has discovered that subordinate (隶属的)fish voluntarily diet to avoid challenging their larger competitors. “In studying gobies we noticed that only the largest two individuals, a male and female, had breeding(繁殖) rights within the group, ”explains Marian Wong. “All other group members are non-breeding females, each being 5–10% smaller than its next largest competitor. We wanted to find out how they keep this size separation.”

The reason for the size difference was easy to see. Once a subordinate fish grows to within 5–10% of the size of its larger competitor，it causes a fight which usually ends in the smaller goby being driven away from the group. More often than not, the evicted fish is then eaten up.

It appeared that the smaller fish were keeping themselves small in order to avoid challenging the boss fish. Whether they did so voluntarily，by limiting how much they ate, was not clear. The research team decided to do an experiment. They tried to fatten up some of the subordinate gobies to see what happened. To their surprise，the gobies simply refused the extra food they were offered，clearly preferring to remain small and avoid fights, over having a feast.

The discovery challenges the traditional scientific view of how boss individuals keep their position in a group. Previously it was thought that large individuals simply used their weight and size to threaten their subordinates and take more of the food for themselves, so keeping their competitors small.

While the habits of gobies may seem a little mysterious, Dr. Wong explains that understanding the relationships between boss and subordinate animals is important to understanding how hierarchical (等级的) societies remain stable.

The research has proved the fact that voluntary dieting is a habit far from exclusive(排他的) to humans. “As yet, we lack a complete understanding of how widespread the voluntary reduction of food intake is in nature,” the researchers comment. “Data on human dieting suggests that, while humans generally diet to improve health or increase attractiveness, rarely does it improve long term health and males regularly prefer females that are fatter than the females’ own ideal.”

1.

When a goby grows to within 5–10% of the size of its larger competitor, it_______.

A. faces danger                 B. has breeding rights

C. eats its competitor          D. leaves the group itself

2.

The underlined words “the evicted fish” in Paragraph 3 refer to _______.

A. the fish beaten up           B. the fish found out

C. the fish fattened up             D. the fish driven away

3.

The experiment showed that the smaller fish_______.

A. fought over a feast             B. went on diet willingly

C. preferred some extra food  D. challenged the boss fish

4.

What is the text mainly about?

A. Fish dieting and human dieting.    B. Dieting and health.

C. Human dieting.                      D. Fish dieting.