Scientists at Royal Holloway, University of London and Queen Mary, University o
题型：不详难度：来源：
The traveling salesman must find the shortest route that allows him to visit all locations on his route. Computers solve it by comparing the length of all possible routes and choosing the shortest, and it can keep computers busy for days. However, bees solve it without computer assistance using a brain the size of grass seed. Dr. Nigel Raine, from the School of Biological Sciences at Royal Holloway explains, “Bees solve traveling salesman problems every day. They visit flowers at multiple locations and because bees use lots of energy to fly, they find a route which keeps flying to a minimum. ”
The team used the computer to control artificial flowers to test whether bees would follow a route defined by the order in which they discovered the flowers or if they would find the shortest route. After exploring the location of the flowers, bees quickly learned to fly the shortest route.
As well as improving our understanding of how bees move around the landscape pollinating(授粉)crops and wild flowers, this research, which is due to be published in The American Naturalist, has other applications. Our lifestyle relies on networks such as traffic on the roads, information flow on the Web and business supply chains. By understanding how bees can solve their problems with such a tiny brain, we can improve our management of these everyday networks without needing lots of computer time. Dr. Raine adds, “Despite their tiny brains, bees are capable of extraordinary feats of behavior. We need to understand how they can solve the traveling salesman problem without a computer. ”
小题1: What would be the best title of the passage?
| A．Bees help salesmen travel |
| B．Tiny-brained bees solve a complex mathematical problem |
| C．How bees discover the flowers |
| D．How to solve the “traveling salesman problem” |
| A．can be solved by a computer easily |
| B．can’t even be solved by a computer |
| C．can puzzle both people and computers |
| D．remains to be solved by scientists |
| A．provide further proof for the research |
| B．tell us how bees can fly the shortest route between flowers |
| C．tell us how the research about bees’ flying route was conducted |
| D．explain the importance of the research |
| A．all creatures are smarter than computers |
| B．the research about bees’ flying route can be applied to many fields |
| C．our networks are more complex than bees’ ones |
| D．with the help of the computer we can find out how bees can solve the “traveling salesman problem” |
答案
小题1:B
小题2:C
小题3:D
小题4:B
解析
小题1:选B。主旨大意题。“销售员旅行难题”用计算机也得需要几天才能解决, 而蜜蜂毫不费力地就能在花丛中找到最近的飞行路线, 故B项“具有微小大脑的蜜蜂解决了一个复杂的数学难题”作为文章的标题最贴切。
小题2:选C。细节理解题。根据第二段可知, 销售员在出发之前必须找到合适的路线, 这个“销售员旅行难题”即使电脑也需要好几天才能解决。
小题3:选D。推理判断题。最后一段说明了对蜜蜂飞行路线研究的意义和目的, 是为了帮助我们在实际生活中更好地节省时间和精力。
小题4:选B。推理判断题。根据最后一段可以推断出对蜜蜂飞行路线的研究可以应用到其他领域中。
举一反三
Ever since the “Back to the Future” movies lit up our screens in the 1980s, designers have dreamt of cars that could take to the sky at the push of a button(按钮). And now pilots can order their own “roadable” plane for just￡127, 000.
The plane, which has fold-out wings that span 17. 5 feet, can be up to 115 mph. Back on the land, it can also travel at “highway speeds” in car mode(模式).
Fuelling(加燃料)the 19 feet long plane couldn’t be simpler—you just drive it into a petrol station and fill it up.
A spokeswoman said, “You can keep your ‘light-sport airplane’ in your garage. But because it needs a short runway to take to the air, you will have to drive to your local airport, fly up to 460 miles, land and drive directly to your destination(目的地). You will always be ready to drive or fly. ”
The spokeswoman added, “Never let bad weather change your trip. You can simply divert(使转向)and continue on the ground until the weather clears. ”
There’s no risk to you—this is only the chance for you to be the first at your home field to unfold(展开)your wings and fly into the future.
小题1:According to the text, the “roadable” plane .
| A．can fly in the sky at “highway speeds” in car mode |
| B．is a kind of car with fold-out wings |
| C．is a little difficult to fuel |
| D．can only travel on the highway |
| A．there are some skillful pilots |
| B．pilots have no cars to drive |
| C．pilots can’t afford a “roadable” plane |
| D．cars can fly in the sky |
| A．Light-sport airplane. |
| B．Your garage. |
| C．The local airport. |
| D．A petrol station. |
| A．call for people to buy the “roadable” plane |
| B．show people the use of the “roadable” plane |
| C．tell people only the “roadable” plane can fly in the future |
| D．ask people to unfold their wings and fly into the future |
| A．land in a nearby airport until it clears |
| B．turn back home until it clears |
| C．land and drive on the ground |
| D．fly high up to 460 miles |
Some people believe that the Mars could support life in the future if the right conditions were produced. The first step would be to warm the planet using certain gases which trap the Sun’s heat in the planet’s atmosphere. With warmth, water and carbon dioxide, simple plants could begin to grow. These plants could slowly make the Mars fit to live on. It is judged that the whole process might take between
100, 000 and 200, 000 years. In the meantime, people could begin to live on the planet in a special closed environment. They would provide a lot of useful information about conditions on the Mars and the problems connected with living there.
小题1: According to the passage, the planet Mars has no on it.
| A．winds | B．dust |
| C．mountains | D．animals |
| A．there is a large amount of ice at the poles |
| B．there is a thicker and warmer atmosphere |
| C．there are some kinds of simple plants |
| D．there are many active volcanoes |
| A．Certain gases should be used to warm the Mars. |
| B．Plants should be grown to make the Mars fit to live on. |
| C．The Mars could support life on right conditions in the future. |
| D．People could live on the Mars in a special closed environment. |
| A．No Life on the Mars |
| B．Study of the Mars |
| C．The Possibility of Life on the Mars |
| D．Future Conditions on the Mars |
The effect of a conversation between a child and an adult is about six times as great as the effect of adult speech input(输入)alone, the researchers found. “Adults speaking to children helps language develop, but what matters much more is the interaction, ”said the study’s lead author, Frederick Zimmerman, an associate professor in the School of Public Health at the University of California, Los Angeles. The researchers also found that TV viewing didn’t have much of an effect—positively or negatively—as long as it wasn’t displacing conversations between an adult and a child.
The UCLA study included 275 families with children between 2 months and 48 months old. They represented a variety of incomes and education. The researchers found that, in an average day, children heard about 13, 000 spoken words from adults and participated in about 400 adult-child conversations a day.
Assessed separately, factors positively associated with language development included each additional 100 conversations a day and each 1, 000 words increase in the number of words spoken by adults and heard by children. When looked at alone, TV was negatively associated with language development. But, when these three factors were analyzed together, the only one that stood out was conversation between adults and children.
“The more a child speaks and interacts with an adult, the better idea a parent has about where the child is”, Zimmerman said. “Although it’s mostly done unconsciously, parents will provide feedback and correct mistakes. They’ll also tailor their speech to the child. Parents can give the children words by talking to them about what they’re doing, such as, ‘I’m putting on your pajamas now’. But give your child the opportunity to talk, hopefully without the rest of the noise in the environment, ”she added. “If parents can carve out some conversation time—maybe at bath time or at dinner time—that’s a wonderful thing. ”
小题1: The researchers also found that TV viewing .
| A．could have a positive effect on a child’s language development |
| B．had a little effect on a child’s language development |
| C．affected a child’s language development more negatively than positively |
| D．affected a child’s language development both negatively and positively |
| A．parents should let their children talk most of the time |
| B．children should watch TV programs selectively |
| C．the conversation between parents and children should be two-way |
| D．it’s no good for parents to correct their children’s mistakes when they are speaking |
| A．parents should let a child repeat what he or she says |
| B．bath time or dinner time is the best chance for parents to talk to a child |
| C．parent-child conversation can be carried out at any proper time |
| D．parents should leave a child talking alone |
| A．Talk with kids, not at them |
| B．Let your children voice their own opinions |
| C．How to develop a child’s language ability |
| D．The importance of early child language development |
| A．control | B．improve |
| C．pass | D．adjust |
Another fungal disease is more serious. Panama disease attacks the roots of the banana plants. There is no chemical treatment for this disease. Infected plants must be destroyed. Panama disease has affected crops in Southeast Asia, Australia and South Africa. There is concern that it may spread to bananas grown in the Americas. This could threaten an important export product for Central and South America.
The International Network for the Improvement of Banana and Plantain supports research on bananas. The group has headquarters in France and other offices in the major banana-growing areas of the world. The group says that more research must be done to develop improved kinds of bananas. The group says that fungal diseases mainly affect only one kind of banana. In fact, there are five hundred different kinds of bananas. Food and Agriculture Organization of the United Nations has said that the Cavendish banana represents only 10% of world production.
The U. N. agency says farmers should grow different kinds of bananas. This protects against diseases that affect only one kind. Experts warn that disease may cause the Cavendish banana to disappear. This happened earlier to another popular banana because of its genetic weakness against disease.
小题1:What does this passage mainly tell us?
| A．Bananas are the world’s most important food crops. |
| B．The risk to a popular banana shows need to grow other kinds. |
| C．There are five hundred different kinds of bananas. |
| D．How to grow bananas in different countries. |
| A．they grow from seeds |
| B．they are one of the most valuable exports |
| C．the only way to prevent it is to put chemicals on their leaves |
| D．they have genetic weaknesses against disease |
| A．doesn’t belong to fungal disease |
| B．affects the leaves of banana plants |
| C．destroys bananas more seriously than Black Sigatoka disease |
| D．has spread to bananas all over the world |
| A．the center of the group is in the US |
| B．the Cavendish banana covers only a small part of the yield of bananas |
| C．the key to solving the disease is to research all kinds of bananas |
| D．each fungal disease affects five hundred different kinds of bananas |
Noah’s Ark was aimed at collecting eggs, embryos(胚胎), semen and DNA of endangered animals and storing them in liquid nitrogen. If certain species should become extinct, Dr. Duane Kraemer, a professor in Texas A & M’s College of Veterinary Medicine, said there would be enough of the basic building blocks to reintroduce the species in the future.
It was estimated that as many as 2, 000 species of mammals, birds reptiles would become extinct in over 100 years. The panda, native only to China, was in danger of becoming extinct in the next 25 years.
This week, Chinese scientists said they grew an embryo by introducing cells from a dead female panda into the egg cells of a Japanese white rabbit. They were then trying to implant the embryo into a host animal.
The entire procedure could take from three to five years to complete.
“The nucleus transfer(核子移植)of one species to another is not easy, and the lack of available(capable of being used)panda eggs could be a major problem,”Kraemer believed. “They will probably have to do several hundred transfers to result in one pregnancy(having a baby). It takes a long time and it’s difficult, but this could be groundbreaking science if it works. They are certainly not putting any live pandas at risk, so it is worth the effort, ”added Kraemer, who was one of the leaders of the project at Texas A& M, the first-ever attempt at cloning a dog.
“They are trying to do something that’s never been done, and this is very similar to our work in Noah’s Ark. We’re both trying to save animals that face extinction. I certainly appreciate their effort and there’s a lot we can learn from what they are attempting to do. It’s a research that is very much needed. ”
At present, the project has worked. The number of the pandas has increased to more than 1, 500.
小题1:The aim of “Noah’s Ark” project was to .
| A．make efforts to clone the endangered pandas |
| B．save endangered animals from dying out |
| C．collect DNA of endangered animals to study |
| D．transfer the nucleus of one animal to another |
| A．available panda eggs | B．host animals |
| C．qualified researchers | D．enough money |
| A．China’s Success in Pandas Cloning |
| B．The First Cloned Panda in the World |
| C．Exploring the Possibility to Clone Pandas |
| D．China—the Native Place of Pandas Forever |
| A．Kraemer and his team had succeeded in cloning a dog |
| B．scientists tried to implant a panda’s egg into a rabbit |
| C．Kraemer would work with Chinese scientists in clone researches |
| D．about two thousand species would probably die out in a century |
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