People who have lost the ability to understand or use words due to brain damage are called aphasics（失语症患者）.Such patients can be extremely good at something else.From the changing expressions on speakers' faces and the tones of their voices,they can tell lies from truths.

    Doctors studying the human brain have given a number of examples of this amazing power of aphasics.Some have even compared this power to that of a dog with an ability to find out the drugs hidden in the baggage.

    Recently,scientists carried out tests to see if all that was said about aphasics was true.They studied a mixed group of people.Some were normal;others were aphasics.It was proved that the aphasics were far ahead of the normal people in recognizing false speeches—in most cases,the normal people were fooled by words,but the aphasics were not.

    Some years ago,Dr.Oliver Sacks wrote in his book about his experiences with aphasics.He mentioned a particular case in a hospital.Some aphasics were watching the president giving a speech on TV.Since the president had been an actor earlier,making a good speech was no problem for him.He was trying to put his feelings into every word of his speech.

    But his way of speaking had the opposite effect on the patients.They didn't seem to believe him.Instead,they burst into laughter.The aphasics knew that the president did not mean a word of what he was saying.He was lying!

    Many doctors see aphasics as people who are not completely normal because they lack the ability to understand words.However,according to Dr.Sacks,they are more gifted than normal people.Normal people may get carried away by words.Aphasics seem to understand human expressions better,though they cannot understand words.

【1】A safari park is a park in which wild animals are kept. They are mainly located in east or central Africa. They often occupy a very wild area, with mountains and rivers. To visit the park and look at the animals, people have to drive around in a car for a few of hours because the park is huge.

【2】In south Africa there is a safari park, which contains all sorts of wild animals like lions, elephants, rhinoceroses(犀牛), zebras, wild pigs, deer and giraffes.

【3】There is a wild road leading through the park, but nobody is permitted to walk on the road. Anyone traveling in the park has to go in a car because wild animals may fiercely attack people. From the car he may see almost every types of African wildlife. Some of these are getting scarce (稀有的) because people kill them for various reasons. For example, rhinoceroses are killed for their horns (角), which are used in traditional Chinese medicines for colds and headaches. Perhaps they will be seen only in museums and books one day.

【4】Travels may buy food for the animals. They can feed them when they tour the park. Of course, they should not feed them in a close distance because the wild animals may attack people. In addition, they should only give proper food to the animals.

【5】A traveler may carry a gun with him in his journey. The gun is given to him by the government. However, it is not used for hunting. In fact, a seal(封条) is fixed to it. The traveler may fire at a wild beast to defend himself in case he is attacked. However, he has to prove to the government that he has been attacked and that he has not fired at a harmless animal.

    Taxi-booking app Uber agreed to sell its business in China to Didi Chuxing. The two firms had been fierce competitors, but Didi Chuxing had controlled the Chinese market with an 87% share.

    Uber China launched in 2014, but it had failed to make any profit for a long time. Cheng Wei, founder and chief executive of Didi Chuxing, said the two companies had learned a great deal from each other over the past two years in China. He added that the deal would set the mobile transportation industry on a healthier path of growth at a higher level. As part of the deal, Mr. Cheng would join the board of Uber, while Uber chief executive Travis Kalanick would also join Didi's board.

    Uber's China business would own its separate branding while US-based Uber Technologies would hold about 17.5% in the combined company. Didi Chuxing is backed by Chinese Internet giants Tencent and Alibaba.

    Uber had been struggling to break into the Chinese market despite having Chinese search engine Baidu as an investor. Last February, the company admitted it was losing more than $1 billion a year in China. “Funding their Chinese dreams was becoming too expensive for Uber,” Duncan Clark, chairman of Beijing-based consultancy BDA, told the BBC. Travis Kalanick said, “As a businessman, I've learned that being successful is about listening to your head as well as following your heart.”

    The fierce competition had led both companies to spend much more on their journeys. The combination is likely to see fewer such subsidies（补贴）. “One thing to watch carefully is how quickly consumers feel the impact as subsidies are withdrawn.” Mr. Clark added.

    The deal with Didi Chuxing came just days after China had agreed to provide a legal framework for taxi-ordering apps. Both Uber and Didi welcomed the decision. The new rules took effect last November and could, among other things, forbid such platforms to operate below cost.

    Some materials are obtained from natural resources that are changed by chemical processes in a laboratory. The resulting artificial materials are synthetic, or human-made.

    Plastic is a synthetic substance, obtained from petroleum, a fossil fuel. The molecules（分子）in petroleum are split and then linked into chains. Plastic is an example of a polymer, a material made of repeating patterns of atoms linked together. Most polymers are synthetic. They are made by polymerization, the process of chemically linking many smaller molecules to form a larger molecule that has different physical features. Some polymers, such as proteins, occur naturally.

    Plastic is a key component of many products. When heated into an almost-liquid form, plastic can be made into fibers, sheets, or molds（模具）. It can be mixed with other elements to remain flexible, or it can harden into a solid. Plastic fibers can be made into clothing or carpeting. Sheets of plastic can be made into plates. Molded plastic can be sued for protective helmets or car bumpers.

    Most plastics can be reheated and remolded repeatedly. This feature makes plastic very easy to use. Polymers can be pulled into fine strings or molded into almost any kind of shape. For example, tubes of plastic can be shaped into bottles by different processes. One such process is extrusion blow-molding. Most plastics are also resistant to many chemicals that might harm other materials. This quality is the reason that so many cleaning liquids are packaged in plastic bottles.

    Plastics are good insulators that can stop electricity or heat to pass through. Look around your kitchen, and observe where plastics are used. Pot handles are sometimes made of plastic, as are cooking tools, toaster controls, and microwave cookware. Food-storage wraps and containers may be made of plastic. Take a walk outdoors, and note all the plastic items you see. Gardening tools, such as watering cans and sprayers, are often made of plastic. Swings and slides made of plastic do not become as hot as metal, so they are safer for play. Because plastics can be heated, remolded, and made into something else, they can be recycled and reused.

    Fish have different personalities which change as they experience life's highs and lows, according to British biologists.

    Researchers identified different "personalities" in their fish by observing the boldness(大胆) or shyness of individuals, according to The Nature. Like people, some fish are very confident in the face of novelty or conflict, while others are silent and fearful.

    The scientists selected particularly bold and shy rainbow trout(虹鳟鱼), and tested whether they changed their outlook depending on what life threw at them. They arranged some fish to fight and others to watch to see how both the participants and observers responded to victories and defeats. Winning or losing a fight, or even watching fellow fish overcome the difficulties influenced the future behavior of the creatures studied in the lab.

    The researchers made fish compete with much larger or smaller opponents(对手), to ensure that they would win or lose their fights. These bold fish that won their fights tended to be even bolder when later presented with a novel food item; losing their fight caused them to be much more cautious.

    Fish also learn by watching others. Bold fish watching a shy fish exploring a mystery object were much more nervous when later given a novel item for themselves.

    Predictably, shy fish that won a fight also gained more confidence, but surprisingly, shy fish that lost their fights also grew bolder when exploring strange new food, Sneddon said, adding that this could be due to what she calls a "desperado effect"(亡命徒效应).

    The new research suggests that animals can gradually adapt(使适应) their personalities. The results agree with the effects that life experience can have on humans.