Cyclist Alain Such has been dropped from the Ingotel cycling team for two years after a positive drug test at the Institute of drug Free Sport. “ I was flabbergasted.” Said Didier Garcia, from Team Ingotel. “Alain joined our team last month and we had no idea that he was being examined.”

    It's a story that has become more and more familiar in recent years. Dr. Mohammad Farnood, a leading sports scientist from Cairo, Egypt, said, “ It is thought that some athletes will look for other ways to improve performance in addition to using drugs.”

    However, it has not always been against the law. In the Olympics in 1904, Thomas Hicks won the marathon after using drugs in the middle of the race. In fact, the first one didn't make him feel better for long, so he was given another and, as a result, he fell down soon after finishing and knew nothing. Another one may well have killed him.

    Things are very different today. Some scientists are considering the possibilities of using genetic engineering to further develop athletes' abilities. “If it works with no risk of discovering,” said Dr Farnood, “ then it's likely to become common practice for athletes.”

    Researchers are looking at the possibility of identifying “athletic” genes and correcting weak ones. Put into practice, this would make a person healthier and stronger. Once scientists understand what genes of top athletes look like , it might even become possible to identify “athletic” genes in young people, and then money could be spent on children who have the most promising genes.

    “People are beginning to recognize that genetics can in many ways do good to our society, for example in saving lives and in creating better quality food for people.” Dr Farnood says. “ So, is it fair to use genetic engineering in sport? You could ask if it's fair for some runners to use the latest scientifically developed footwear. The key question is whether it's available to everyone.”

根据短文内容，选择最佳答案，并将选定答案的字母标号填在题前括号内。

    Children start out as natural scientists, eager to look into the world around them. Helping them enjoy science can be easy; there's no need for a lot of scientific terms or expensive lab equipment. You only have to share your children's curiosity. Firstly, listen to their questions. I once visited a classroom of seven-year-olds to talk about science as a job. The children asked me “textbook questions” about schooling, salary and whether I liked my job. When I finished answering, we sat facing one another in silence. Finally I said, “Now that we're finished with your lists, do you have questions of your own about science?”

    After a long pause, a boy raised his hand, “Have you ever seen a grasshopper （蚱蜢）eat? When I try eating leaves like that, I get a stomachache. Why?”

    This began a set of questions that lasted nearly two hours.

    Secondly, give them time to think. Studies over the past 30 years have shown that, after asking a question, adults typically wait only one second or less for an answer, no time for a child to think. When adults increase their “wait time” to three seconds or more, children give more logical, complete and creative answers.

    Thirdly, watch your language. Once you have a child involved in a science discussion, don't jump in with “That's right” or “Very good”. These words work well when it comes to encouraging good behavior. But in talking about science, quick praise can signal that discussion is over. Instead, keep things going by saying “That's interesting” or “I'd never thought of it that way before”, or coming up with more questions or ideas.

    Never push a child to “Think”. It doesn't make sense, children are always thinking, without your telling them to. What's more, this can turn a conversation into a performance. The child will try to find the answer you want, in as few words as possible, so that he will be a smaller target for your disagreement.

    Lastly, show; don't tell. Real-life impressions of nature are far more impressive than any lesson children can learn from a book or a television program. Let children look at their fingertips through a magnifying glass（放大镜）, and they'll understand why you want them to wash before dinner. Rather than saying that water evaporates（蒸发）, set a pot of water to boil and let them watch the water level drop.

    A recent study led by researchers from the National University of Singapore (NUS) has found a clear link between the color of a taxi and its accident rate. An analysis of 36 months of detailed taxi, driver and accident data from two fleets of yellow and blue taxis in Singapore suggested that yellow taxis have fewer accidents than blue taxis. The higher visibility (能见度)of yellow makes it easier for drivers to avoid getting into accidents with yellow taxis, leading to a lower accident rate.

    The study was led by Prof Ho. To test whether there was a causal relationship between the color of a taxi and the number of accidents the taxi had, the research team analysed data collected by the largest taxi company in Singapore. The researchers found that yellow taxis have about 6.1 fewer accidents per 1,000 taxis per month.

    The researchers also studied the economic effect of changing the color of the entire fleet of taxis to yellow. The Singapore taxi company involved in the study owns about 16,700 taxis in a ratio(比例) of one yellow to three blue taxis. If a commercial decision is made to switch from blue to yellow taxis, 76.6 fewer accidents would occur per month or 917 fewer accidents per year. Assuming an average repair cost of $1,000 per car and a downtime of six days, switching the color of all taxis to yellow could produce an annual savings of $2 million.

    "We are eager to continue to validate(证实) the findings of our study by looking at the use of yellow in other types of public transport, such as school buses. For instance, we hope to compare the accident rates of yellow school buses against other colors to find out if yellow is indeed a safer color for school buses. Besides, we are also interested to look at private-hire vehicles and do a comparison of the accident rates of vehicles that are of different colors," explained Prof Ho.

    A company in San Francisco, California, has found a way to turn used plastic bottles into women's shoes.

    Every day, millions of Americans drink water and other liquids from plastic bottles. More than 60 million of them are thrown away each day. Many of the plastic bottles end up in landfills or are burned with other waste products.

    A San Francisco start-up company called Rothy's, however, turns this plastic waste into environmentally friendly shoes. Roth Martin is the company's co-founder. He explains how they turn plastic into soft material for women's feet. They take the plastic, clean it, and break it down into small pieces. Then they press them through a device that makes soft fibers. Those fibers arc then combined together. This is done by a 3D machine. It is designed to reduce waste while making the shoes. The knitted stuff and the inner part of the shoe arc then attached to the shoe's outer part, called the sole (鞋底).This outer sole is also made from environmentally friendly material: responsibly responsibly sourced no-carbon rubber.

    Rolhy's shoes are sold online. They are flat shoes, with either a rounded or pointed toe. They come in different colors and designs. They cost either $ 125 or $ 145 per pair, depending on the design. After American actress Gwyneth Paltrow discovered them last year, the demand for the shoes grew. Martin says there is no shortage of material to fill that demand. "We're not going to run out of water bottles any time soon. So we have a limitless supply of material, and I think that is a good sign for our future." When the environmentally friendly shoes wear out, customers can return them at no cost to a company that uses the recycled material to make other products.

    For now, the shoes are only available to be shipped in the United States. However, the company says it will add international shipping in the near future.

Learning New Vocabulary during Deep Sleep

    Sleeping time is sometimes considered unproductive time. This raises the question whether the time spent asleep could be used more productively, e.g. for learning a new language? Up-to-now sleep research focused on the stabilization and strengthening of memories that had been formed during wakefulness. However, learning during sleep has rarely been examined. There is enough evidence for wake-learned information undergoing a revision by replay in the sleeping brain. The replay during sleep strengthens the still weak memory and leaves the newly acquired information in the pre-existing store of knowledge.

    If re-play during sleep improves the storage of wake-learned information, then first-play, i.e. the initial processing of new information, should also be possible during sleep.

    The research group of Katharina Henke examined whether a sleeping person is able to form new semantic（语义的）associations between played foreign words and translation words during the brain cells' active states, the so-called "Up-states." It turned out to be that what they thought was reasonable. When we reach deep sleep stages, our brain cells progressively coordinate their activity. During deep sleep, the brain cells are commonly active for a brief period of time before they jointly enter into a state of brief inactivity. The active state is called "Up-state" and the inactive state "Down-state". The two states alternate（交替）about every half-second.

    New evidence for sleep-learning challenges current theories of sleep and theories of memory. The concept of sleep that we are separated from the physical environment is no longer reasonable. "It's false that complex learning be impossible during deep sleep," says Simon Ruch, co-first-author. "In how far and with what consequences deep sleep can be applied for the acquisition of new information will be a topic of research in upcoming years," says Katharina Henke.

    The research group of Katharina Henke is part of the Interfaculty Research Cooperation (IRC). Thirteen research groups in medicine, biology and psychology are part of the IRC. The aim of these research groups is to gain a better understanding of the mechanisms（原理）involved in sleep and consciousness.

Kindle E-reader, 8th generation

    Free Touchscreen Display

    Price: $79. 99

    ● Thin and light for one-handed reading

    New Kindle is 11% thinner and 16% lighter than the previous generation Kindle, making it easy and comfortable to hold in one hand.

    ● Read like real Paper

    Kindle creates text similar to what you see in a physical book. The blacks and whites on the screen are uniform, improving text and image quality.

    ●Long-life battery

    Kindle doesn't need power to show a page of text, allowing you to read for weeks on a single charge.

    ● Thousands of books, no distraction (分心)

    Kindle is designed to be an e-reader. It satisfies your love of reading without interruptions like e-mails and phone calls.

    ●Look it up without leaving your page

    Smart Lookup combines entries from The New Oxford American Dictionary with information from Wikipedia, so you can know meanings, characters and more without losing your place.

    ●Adjust your text size

    Choose from eight text sizes to prevent tired eyes, so you can keep reading longer.

    Customer reviews:

    ※ Damon, May 21, 2019

    The price is great with an extra $ 20 off and this new Kindle is smaller in my hands than my old one. I was sad to lose my old Kindle, but this one is terrific.

    ※ Jason, January 26, 2019

    I miss the original Kindlers size—this one is too small. Also, the screen is overly sensitive and things pop up (弹出) and the battery doesn't last as long as the original Kindle. But my biggest disappointment is that this Kindle doesn't allow you to transfer everything from the original Kindle、so I lost all of the information from my old one. Overall, disappointing.

    ※ Susan, November 17, 2018

    I had the original Kindle, and the battery lasted for weeks. This battery only seems to last a few days, however. The other problem I have with this version of the Kindle is the touch screen. It is annoying when you are reading and start turning the wrong way. Sometimes, it's hard to get the page to turn the way you'd like it to.