Long-time exposure to air pollution can lead to physical changes in the brain and cause trouble in learning and memory, and even anxiety. This is suggested by the results of new research on mice. While other studies have shown the harmful effects of polluted air in the lungs and heart, this is the first to show the negative effect on the brain. The team of Laura Fonken, Randy Nelson , from the Ohio State University, the USA, has spread to the brain a previous line of research which found that fine particulate matter floating in the air mainly because of air pollution caused by humans, causes swelling in much of the body, and may be related to high blood pressure problems, and some other diseases. In the research Fonken and his colleagues exposed mice to polluted air for six hours each day, five days a week, over a period of 10 months, almost half the average life length of mice. Polluted air contains fine particles created by cars, factories and natural dust. Fine particles of this kind are tiny, about 2.5 micrometers in diameter , or about one-thirtieth the width of a human hair. These particles can go deep into lungs and other organs. The concentration of this particulate material to which they exposed mice is equal to the concentration at which people can be exposed in some polluted urban areas. After a period of 10 months, the researchers got the animals to have a series of behavioral tests. Both the behavior of mice and the results of neurological tests done to them show that those within the polluted air had more problems in learning and memory, and higher levels of anxiety. The results suggest that long-time exposure to polluted air can have measurable negative effects on the human brain and can cause a variety of mental health problems. This could have important consequences for those living and working in polluted urban areas. What harmful effect of polluted air is mentioned in other studies? A) The harmful effect on learning. B) The harmful effect on all the organs. C) The harmful effect on lungs and heart. D) The harmful effect on improving memory.
C
American scientists have developed the first material that repairs itself. The material is a form of plastic that has been engineered to fill breaks in its surface. Plastics are used today in everything. Scientists wanted to find a way to make objects made of plastic last longer. The researchers hope their new discovery can be used to make objects that are difficult or impossible to replace. The surface of plastic objects breaks over time. Very small breaks develop every time a plastic object is used. The researchers wanted to find out how to stop plastic from developing small breaks that weaken and destroy it. They found the answer in the chemical structure of plastic itself. The research team found a way to make plastic that contains very small balloons filled with monomer liquid. When the new plastic cracks, the monomer liquid is let out and flows into the crack. Thus the break is repaired. The repaired plastic has seventy-five percent of the strength of undamaged plastic. The new self-repairing plastic is not yet ready for production. But it has several possible uses. One could be in space vehicles where parts cannot be repaired or replaced. Another possible use might be in bridges. And it could be used in people, to replace bone joints that have become broken or damaged. The passage mainly talks about _ . A) plastic that repairs itself B) the chemical structure of plastic C) permanent material invented D) small balloons that makes plastic stronger
A
Q: Kiss crisis, hug horrors and the UK's handshake headaches Greeting someone, saying goodbye - these situations fill me with unease. You have a second to make a dangerous decision. One peck ? Two pecks? Three? No kisses at all? Why, I think, as I crash into the other person's face, why can't it be as simple as a handshake? A survey by the soap company Radox in May showed one in five Brits now feels a handshake is "too formal", according to the Daily Mail. Some 42 percent said they never shook hands when greeting friends. For one third of people the alternative was a hug, for 16 percent a kiss on the cheek. British people are known to be reserved - unfriendly, some would say. Handshakes used to work for us because we didn't have to get too close. But the super-British handshake is no longer fashionable. We want to be more like our easygoing Mediterranean neighbors who greet each other with kisses and hugs. The trouble is, we still find it a bit awkward. What does a married man do when greeting a married female friend, for example? How should someone younger greet someone older? Guys don't tend to kiss one another; my male friends in Britain go for the "manly hug", taking each other stiffly in one arm and giving a few thumps on the back with words like "Take it easy, yeah?". The biggest questions, if you do decide to kiss, are how many times and which cheek first. Unlike the French, who comfortably deliver three, our cheek-pecks usually end in embarrassed giggling : "Oh, gosh, sorry, I didn't mean to kiss you on the lips, I never know where to aim for first!" But then it's never been easy for us poor, uncomfortable Brits. Even the handshake had its problems: don't shake too hard, but don't hold the other person's hand too limply either, and definitely don't go in with sweaty hands. Maybe it's better to leave it at a smile and a nod. Who wrote the article? A) A British writer. B) An American writer. C) A French writer. D) A Chinese writer.
A: A
Q: A boy who was nervous on his first day of school climbed onto a third-floor balcony and put legs over the side. His mother and teachers tried their best to bring him down, but failed. However, a firefighter who dressed as "Spiderman" succeeded in saving him. Firefighter David Smith was called in after the 6-year-old's teachers and mother had failed to get him down from the balcony. "He was asking for his mother, "Smith said. "He was crying, and wouldn't let any of us get near him." After hearing a conversation between the boy's mother and his teachers about his love of superheroes , Smith hurried home to get his Spiderman clothes. "I told him 'Spiderman is here to save you. No one will hurt you now,'" Smith said. "Then I told him to walk slowly toward me. I was really nervous that he might fall if he got too excited and started running." Then the crying boy broke into a smile and walked into the fireman's arms. The fictional superhero was created by writer Stan Lee in the early 1960s. It has recently become popular again through a series of movies made about him. In them he is acted by superstar Tobey Maguire, who acted with Kirsten Dunst and James Franco. Which would be the best title for this passage? A) Spiderman Is Back B) "Spiderman" Saved a Boy C) Spiderman Is Popular D) A Boy's Love of Spiderman
A: B