The highest beef prices in almost three decades have arrived just before the start of the hot season, causing a great shock to both consumers and restaurant owners—and relief isn't likely anytime soon. A decreasing number of cattle and growing export demand from countries such as China and Japan have caused the average price of fresh beef to climb to $5.28 a pound in February, up almost a quarter from January and the highest price since 1987.

    Everything that's produced is being consumed, said Kevin Good, an analyst at CattleFax, a Colorado-based information group. Prices will likely stay high for a couple of years as cattle producers start to rebuild their cattle among big questions about whether the Southwest and parts of the Midwest will see enough rain to water the grass.

    "I quit buying steaks a while ago when the price went up," said 59-year-old Len Markham, who works at Texas Tech. She says she limits red meat purchases to hamburger, choosing chicken, pork and fish instead.

    Restaurant owners, too, must deal with the high prices. Mark Hutchens, owner of the 50 Yard Line Steakhouse in Lubbock, raised his menu prices for beef items by about 5 percent in November. Since then, the owner of the small eating house has tried to make cuts elsewhere to avoid passing it on to customers. "It really puts more pressure on the small guys," he said of non-chain restaurants. "I just think you have to stay competitive and keep your costs low."

    “White-tablecloth restaurants have adjusted the size of their steaks, making them thinner”, says Jim Robb, director of the Colorado-based Livestock Marketing Information Center. “And fast-food restaurants are cutting costs by reducing the number of menu items and are offering other meat options, including turkey burgers, Robb said. Chain restaurants also try to buy beef as much as they can, which essentially gives them a discount”, Iowa State University assistant economics professor Lee Schulz said.

    The high prices are welcome news for at least one group: ranchers(大农场经营者), especially those in Texas who for years have struggled amid drought（干旱） and high feed prices. But even as ranchers breathe a sigh of relief, some worry lasting high prices will cause consumers to permanently change their buying habits — switching to chicken or pork. Pete Bonds, a 62-year-old Texas rancher and president of the Texas and Southwestern Cattle Raisers Association, said that's a big concern. “But such fears may be unfounded, Robb said. “Three years ago, economists thought consumers would start finding substitutions for beef as the drought spread. We're surprised we haven't seen more of that," he said.

    South Dakota rancher Chuck O'Connor thinks that consumers won't abandon beef for good. "I'm sure some are maybe going to cut back some, but to say that people aren't going to buy it anymore, I don't think that's going to happen," he said, adding, "I hope not."

    Recently some American scientists have given a useful piece of advice to people in industrialized nations．They say people should eat more of the same kind of food eaten by humans living more than 10,000 years ago． {#blank#}1{#/blank#}

    The scientists say that the human life has changed greatly．Our bodies have not been able to deal with these changes in lifestyle and this had led to new kinds of sicknesses． {#blank#}2{#/blank#} So they are called “diseases of civilization”．Many cancers and diseases of the blood system are examples of such diseases.

    Scientists noted that people in both the Old Stone Age and the New Stone Age enjoyed very little alcohol or tobacco, probably none． {#blank#}3{#/blank#} However, a change in food is one of the main differences between life in ancient times and that of today.

    Stone Age people hunted wild animals for their meat, which had much less fat than domestic ones．They ate a lot of fresh wild vegetables and fruits．They did not have milk or any other dairy products, and they made very little use of grains． {#blank#}4{#/blank#} We eat six times more salt than our ancestors．We eat more sugar．We eat twice as much fat but only one third as much protein and much less vitamin C.

    {#blank#}5{#/blank#} But scientists say that we would be much healthier if we eat much the same way the ancient people did, cutting the amount of fatty, salty and sweet food.

A．Stone Age people lived a simple life.

B．But today, we enjoy eating a lot of these.

C．In that case, they would live much healthier.

D．Ancient people also got lots of physical exercise.

E．These new sicknesses were not known in ancient times.

F．People today probably don't want to live like our ancestors.

G．Modern people used to suffer from “diseases of civilization”.

    If your dog looks pleased to see you—it is probably because it loves the particular way you smell.

    The scent (气味)of a familiar human apparently lingers like perfumein the animal's brain—where it causes an instinctive emotional response, research reveals.

    Our scent acts on a part of the canine (犬科的) brain associated with reward and the strongest reactions are produced by humans that pets know best, say scientists in America.

    Gregory Bern, of Emory University in Atlanta, said, “While we might expect that dogs should be highly tuned to the smell of other dogs, it seems that the 'reward response' is reserved for their humans. When humans smell the perfume of someone they love, they may have an immediate, emotional reaction that's not necessarily cognitive (认识的). So is it in dogs. But since dogs have a more sensitive smell than humans, their responses would likely be even more powerful than the ones we might have. In our experiment, however, the owners of the dog were not physically present. The canine brain responses were being caused by something distant in space and time. It shows that dogs' brains have these mental representations of us that persist when we're not there.”

    The experiment involved 12 dogs of various kinds by brain scans while five different scents were placed in front of them. The scent samples (样本)came from the subject (接受试险者) itself, a dog the subject had never met, a dog living in the subject's household. The familiar human scent samples were taken from someone else from the house other than the handlers during the experiment, so that none of the scent donors were physically present.

    The results showed all five scents gained a similar response in parts of the dogs brains involved in detecting smells. Responses were significantly stronger for the scent of familiar humans, followed by that of familiar dogs. The findings showed dogs reacted strongest to the scent of familiar humans even when they were not there. Pets trained as help or therapy dogs showed greater brain activity than the other dogs in the test.

    Researchers say the findings could improve the way to select animals helping wounded old soldiers or disabled people.

    Chinese scientists recently have produced two monkeys with the same gene, Zhong Zhong and Hua Hua, using the same technique that gave us Dolly the sheep. These monkeys are not actually the first primates(灵长类)to be cloned. Another one named Tetra was produced in the late 1990s by embryo(胚胎)splitting, the division of an early-stage embryo into two or four separate cells to make clones. By contrast, they were each made by replacing an egg cell nucleus(卵原子核)with DNA from a differentiated body cell. This Dolly method, known as somatic(躯体的) cell nuclear transfer(SCNT), can create more clones and allows researchers greater control over the edits they make to the DNA.

    Success came from adopting several new techniques. These included a new type of microscopy(显微术) to better view the cells during handling or using several materials that encourage cell reprogramming, which hadn't been tried before on primates. Still, the research process proved difficult, and many attempts by the team failed. Just two healthy baby monkeys born from more than 60 tested mothers. This leads to many researchers' pouring water on the idea that the team's results bring scientists closer to cloning humans. They thought this work is not a stepping stone to establishing methods for obtaining live born human clones. Instead, this clearly remains a very foolish thing to attempt, and it would be far too inefficient, far too unsafe, and it is also pointless.

    But the scientists involved emphasize that this is not their goal. There is now no barrier for cloning primate species, thus cloning humans is closer to reality. However, their research purpose is entirely for producing non-human primate models for human diseases; they absolutely have no intention, and society will not permit this work to be extended to humans. Despite limitations, they treat this breakthrough as a novel model system for scientists studying human biology and disease.

    He is regarded as having one of the brightest minds on the planet. But outstanding astrophysicist (天体物理学家) Stephen Hawking has admitted that he did not learn to read until he was eight years old.

    In a public lecture at the Royal Albert Hall, Professor Hawking also admitted that he was not active in studying while at Oxford University, where he studied physics, and that only the diagnosis that he might die young from motor neurone (神经元) disease made him concentrate on his work.

    Professor Hawking said: "My sister Philippa could read by the age of 4 but then she was definitely brighter than me." He said that he was unexceptional at school and was never further than halfway up his class. "My classwork was very untidy, and my handwriting was the despair of my teachers," he said. "But my classmates gave me the nickname Einstein, so presumably they saw signs of something better."

    But he said that it was when doctors told him that he probably only had a few years to live at the age of 21 that galvanized him into focusing on his work and a period of productivity that resulted in some of his early breakthroughs. He said, "When you are faced with the possibility of an early death, it makes you realize that life is worth living and there are lots of things you want to do."

Young people dressed in hanfu, the traditional clothing of the Han ethnic group in China,{#blank#}1{#/blank#} (spot) in many locations around the world during this year's Spring Festival holiday.

An initiative {#blank#}2{#/blank#} (launch) in late January by a Chinese social media platform invited users to upload photos or {#blank#}3{#/blank#} (video) of themselves and friends wearing hanfu at landmarks around the world from January 28 to February 19.

The first two weeks of the initiative saw about 10,000 users share their photos taken from around 30 countries and regions around the world, one of {#blank#}4{#/blank#} even posted photos from Antarctica. Many young Chinese people working or studying overseas also invited their foreign friends to wear traditional Chinese costumes {#blank#}5{#/blank#}(celebrate) the Spring Festival together.

Hanfu, as well as other traditional forms of Chinese costume,{#blank#}6{#/blank#} (experience) a surge（飞涨） in popularity in recent years. Clothes {#blank#}7{#/blank#} (feature) traditional Chinese elements combined {#blank#}8{#/blank#} modern designs, which are called the new Chinese style, have developed into {#blank#}9{#/blank#} fashion. trend among the younger generations not only in China, but also worldwide.

Analysts say the rise of "China chic" {#blank#}10{#/blank#} (definite) reflects young Chinese people's confidence in their own culture. Wearing Chinese-style costumes reflects the wearer's Eastern temperament, and presents Chinese aesthetics to the world.