After years of heated debate, gray wolves were reintroduced to Yellowstone National Park. Fourteen wolves were caught in Canada and transported to the park. By last year, the Yellowstone wolf population had grown to more than 170 wolves.

Gray wolves once were seen here and there in the Yellowstone area and much of the continental United States, but they were gradually displaced by human development. By the 1920s , wolves had practically disappeared from the Yellowstone area. They went farther north into the deep forests of Canada, where there were fewer humans around.

The disappearance of the wolves had many unexpected results. Deer and elk populations ---major food sources (来源) for the wolf – grew rapidly. These animals consumed large amounts of vegetation（植被）, which reduced plant diversity in the park. In the absence of wolves, coyote（郊狼）populations also grew quickly. The coyotes killed a large percentage of the park’ s red foxes, and completely drove away the park’ s beavers.

As early as 1966, biologists asked the government to consider reintroducing wolves to Yellowstone Park. They hoped that wolves would be able to control the elk（麋鹿） and coyote problems. Many farmers opposed the plan because they feared that wolves would kill their farm animals or pets.

The government spent nearly 30 years coming up with a plan to reintroduce the wolves . The U.S. Fish and Wildlife Service carefully monitors and manages the wolf packs in Yellowstone. Today, the debate continues over how well the gray wolf is fitting in at Yellowstone. Elk, deer, and coyote populations are down, while beavers and red forests have made a comeback. The Yellowstone wolf project has been a valuable experiment to help biologists decide whether to reintroduce wolves to other parts of the country as well.

This is Copycat, a kitten who will go down in history. The two-month-old kitten, with blue eyes and a pink button nose, looks like any other kitten. But Copycat is a pioneer of commercial (商业的，盈利的)cloning. She means that cats of the future could have more than nine lives.

The company which produced her ---by the same technique as Dolly the Sheep ---plans to charge wealthy pet owners thousands of pounds to replicate （复制）animals that have died. They are already working on a cloned dog.

Copycat was created in a laboratory at the Texas A&M University. She is a copy of an adult cat from which DNA was removed, and is quite different from the surrogate mother（代孕母亲）who gave birth to her. Despite having identical genes to the adult cat, Copycat has slightly different patterns on her cream and coat（皮毛）. The Texas team say this is because the patterns are the result of the kitten’s natural development as well as genetics（遗传）.

Copycat’s creation was financed by 81-year-old John Sperling, who owns a company called Genetic Savings & Clone. He plans to offer the technology to wealthy people seeking to replace beloved pets. He also wants to replicate “socially-valuable” animals such as search-and-rescue dogs.

Experts predict that commercial pet cloning will become widely available in just a few years and claim that it will be the first breakthrough in the field to directly benefit the public. However, the breakthrough raises more concerns about how cloning techniques are being used. Critics have considered the work as disturbing the mature and a waste of scientific resources. They warn that cloned pets, even if they are genetically identical to the animals they are meant to replace, could be quite different in character and behavior. The UK’s Animal Procedures Committee says cloning for “trivial purposes” such as pets should be banned and that cloning should be used to help people solve some big and life-threatening problems.

  Is there anything more important than health? I don't think so. "Health is the greatest wealth." wise people say. You can't be good at your studies or work well when you are ill. If you have a headache, toothache, backache, earache or bad pain in the stomach, if you complain of a bad cough, if you run a high temperature and have a bad cold, or if you suffer from high or low blood pressure, I think you should go to the doctor. The doctor will examine your throat, feel your pulse, test your blood pressure, take your temperature, sound our heart and lungs, test your eyes, check your teeth or have your chest X-rayed. After that he will advise some treatment, or some medicine. The only thing you have to do is to follow his advice.

Everyone becomes a little more forgetful as they get older, but men’s minds decline more than women’s, according to the results of a worldwide survey.

       Certain differences seem to be inherent in male and female brains: men are better at dealing with mental images (useful in mathematical reasoning and spatial (三维空间) skills), while women tend to excel (擅长) at recalling information from their brain’s files (helpful with language skills and remembering the locations of objects).

       Many studies have looked for a connection between sex and the amount of mental decline people experience as they age, but the results have been mixed.

       Some studies found more age-related decline in men than in women, while others saw the opposite or even no relationship at all between sex and mental decline. Those results could be improper because the studies involved older people, and women live longer than men. The men tested are the survivors, “so they’re the ones that may not have shown such cognitive (认知的) decline,” said study team leader Elizabeth of the University of Warwick in England.

       People surveyed completed four tasks that tested sex-related cognitive skills: matching an object to its rotated (旋转的) form, matching lines shown from the same angle, typing as many words in a particular category as possible in the given time, e.g. “objects usually colored gray”, and recalling the location of objects in a line drawing. The first two were tasks at which men usually excel; the latter are typically dominated by women.

       Within each age group studied, men and women performed better in their separate categories on average. And though performance declined with age for both sexes, women showed obviously less decline than men overall.

B

Fear may be felt in the heart as well as in the head，according to a study that has found a link between the cycles of a beating heart and the chance of someone feeling fear.
　　Tests on healthy volunteers found that they were more likely to feel a sense of fear at the moment when their hearts are contracting(收缩)and pumping blood around their bodies，compared with the point when the heartbeat is relaxed. Scientists say the results suggest that the heart is able to influence how the brain responds to a fearful event，depending on which point it is at in its regular cycle of contraction and relaxation.
　　Sarah Garfinkel at the Brighton and Sussex Medical School said：“Our study shows for the first time that the way in which we deal with fear is different depending on when we see fearful pictures in relation to our heart.”
　　The study tested 20 healthy volunteers on their reactions to fear as they were shown pictures of fearful faces. Dr Garfinkel said，“The study showed that fearful faces are better noticed when the heart is pumping than when it is relaxed. Thus our hearts can also affect what we see and what we donˈt see—and guide whether we see fear.”
　　To further understand this relationship，the scientists also used a brain scanner to show how the brain influences the way the heart changes a personˈs feeling of fear.
　　“We have found an important mechanism by which the heart and brain ‘speak’ to each other to change our feelings and reduce fear，” Dr Garfinkel said.
　　“We hope that by increasing our understanding about how fear is dealt with and ways that it could be reduced, we may be able to develop more successful treatments for anxiety disorders，and also for those who may be suffering from serious stress disorder.”

Paragraph 6?　

As the saying goes, “An apple a day keeps the doctor away.” That’s because this healthy food choice is supposed to be full of nutrients. The apple at the supermarket, though, might be so old that it has lost many of its nutrients. But soon there might be a way to check the quality of fruit by scanning it.

Scientists at Food+Future coLAB have come up with the idea of a handheld spectrometer (分光仪) that scans food. The machine will work by shining infrared (红外线的) light on a piece of produce. By measuring how chemicals in the fruit or vegetable take in the light, the scanner can recognize the food’s chemical makeup.

“The machine can tell you exactly how old an apple is, how many calories it contains, what nutrients are present inside it, and even small differences in taste,” Greg Shewmaker of Food+Future coLAB recently said.

For the new machine to be useful to consumers, researchers first need to create a database that contains possible chemicals for a particular type of fruit, like an apple, for example. Scientists will need to scan lots of pieces of produce to collect this data. The information collected will allow the scanners to tell customers the quality of fruit.

Once consumers know what’s inside an apple, they can decide if they want to buy it. Knowing fruit quality may also affect how a store prices produce. “We can price produce based on the nutritional value,” Shewmaker explained.

Food+Future coLAB has already created a working model of its machine. It says you may see one in your local supermarket within the next few years. Then deciding whether you’ve picked the healthiest fruit will be just a quick scan.

This weekly four-day physical activity schedule will get your kids excited about being active.

Tuesday

When the kids get home from school, don’t let them go straight to the TV and get settled in. Encourage them to get moving and get off the couch(沙发) by giving them a pedometer(计步器). Pedometers are the most fun when parents also use one because that turns stepping, walking and running into a game to see who can get the most steps.

Thursday

The kids have done a great job so far this week, but now they long for a little more TV time. Instead of turning on cartoons, let them watch fitness movies made just for kids. These movies encourage watchers to get up and dance along to kid-friendly music.

Saturday

Get the whole family out of the house together and over to a park. Bring lots of sports equipment, pack a healthy picnic and have a family competitive sports day. Kids and adults get into groups and play against each other in tennis, basketball or soccer. After everyone has played hard for a couple of hours, stop for a picnic and then if your family isn’t too tired, go back and play some more.

Sunday

Every child loves to play video games and there is no better time to allow kids to play them than on Sunday when no homework is due. But don’t let them play a game that forces them to sit down for hours. Dance games with a floor mat to help kids follow the dance moves are popular to kids.

C

I am Peter Hodes, a volunteer stem cell courier. Since March 2012, I've done 89 trips — of those, 51 have been abroad. I have 42 hours to carry stem cells (干细胞) in my little box because I've got two ice packs and that's how long they last. In all, from the time the stem cells are harvested from a donor (捐献者) to the time they can be implanted in the patient, we've got 72 hours at most. So I am always conscious of time.

I had one trip last year where I was caught by a hurricane in America. I picked up the stem cells in Providence, Rhode Island, and was meant to fly to Washington then back to London. But when I arrived at the check-in desk at Providence, the lady on the desk said: "Well, I'm really sorry, I've got some bad news for you—there are no flights from Washington." So I took my box and put it on the desk and I said: "In this box are some stem cells that are urgently needed for a patient—please, please, you've got to get me back to the United Kingdom." She just dropped everything. She arranged for a flight on a small plane to be held for me, re-routed (改道) me through Newark and got me back to the UK even earlier than originally scheduled.

For this courier job, you're consciously aware that in that box you've got something that is potentially going to save somebody's life.

Which of the following can replace the underlined word "courier" in Paragraph 1?

As skies are filled with millions of migrating(迁徙) birds, European scientists say the seasonal wonder appears to be strange: The fatter the bird, the better it flies.

The results of their study led to a theory opposite to a central one of aerodynamics (空气动力学), which says that the power needed to fly increases with weight.

For birds, obviously, the cost of flying with heavy fat is much smaller than we used to think. Researchers found that red knot wading birds double their normal body weight of 100 grams before making their twice-a-year nonstop flight between the British Isles and the Russian Arctic. Distance: 5,000 kilometers.

Another study in the magazine Nature measured the advantage of flying in an aerodynamic group which allows birds to save energy by flying smoothly and quietly in the lead bird' s air stream.

Flying in groups, their heart rates were 14.5 percent lower than flying alone, according to Henri, a French scientist. The findings help explain how birds complete difficult migrations. Researchers had thought that thinner, stronger birds would have the best chance to survive.

The first study suggests that building up fat to be burnt as fuel during the migration is worth more than the energy it takes to carry the additional weight.

In the study, researchers said their team studied the birds flown at different body weights during 28 simulated(模拟的) flights. They forced a small amount of special water into the birds' bodies so that they could measure the amount of energy burnt during the flight.

C

  In the famous fairy tale, Snow White eats the Queen's apple and falls victim to a curse; in Shakespeare's novel, Romeo drinks the poison and dies; some ancient Chinese emperors took pills that contained mercury, believing that it would make them immortal, but they died afterward.

    Poison has long been an important ingredient in literature and history, and it         seems to always be associated with evil, danger and death. But how much do you really know about poison?

     An exhibition, the Power of Poison, opened last month at the American Museum of Natural History in New York, intended to give the audience a more vivid understanding of poison. The exhibition will continue until Aug 2014, reported The New York Times.

The museum tour starts in a rainforest setting, where you can see live examples of some of the most poisonous animals: caterpillars, frogs and spiders. Golden poison frogs, for instance, aren’t much bigger than a coin, but their skin is covered in a poison that can cut off the signaling power of your nerves, and a single frog has enough venom to kill 10 grown humans.

The exhibition also features interactive activities. In an iPad-based game, visitors are presented with three puzzling illnesses and asked to identify the poisons based on symptoms. In one case, for example, a pet dog is found sick in a backyard and visitors have to figure out whether it was the toad (蟾蜍), the leaky batteries in the trash or the dirty pond water that did it.

      “Poisons can be bad for some things,” Michael Novacek, senior vice president of the museum, told NBC News. “Yet they can also be good for others.”

      This is what visitors learn from the last part of the exhibition, which displays how poisons can be used favorably by humans, including for medical treatment.

      The blood toxins of vampire bats, for example, can prevent blood from clotting (凝结), which may protect against strokes. A poisonous chemical found in the yew tree is effective against cancer, which is what led to the invention of a cancer-fighting drug called Taxol. One chemical in the venom of Gila monsters can lower the blood sugar of its victims, so it has been used to treat diabetes.

      The benefits from natural poisons are not limited to just medicine. Believe it or not, many substances that we regularly take in – chili, coffee and chocolate, etc. – owe their special flavors or stimulating effects to chemicals that plants make to poison insects.

63. By mentioning Snow White and Romeo at the beginning of the story, the author intends to________.

64. What is the main purpose of the exhibition The Power of Poison?

65. Which of the following statements about the exhibition is TRUE according to the article?