The robot moved into the fighting ring  with confidence.Then it turned around quickly and knocked itself over. The team of Scouts  that built the 8-inch -tall machine immediately realized one arm was too long.They would have to work fast---practice time was over , and the real robot  matches were about to begin . "We tried to fix it , but by that time , the other teams had more advanced technology ," says Eagle Scout Matthew Patchen , 16. "They were a couple of steps ahead of us ." In the end , Matthew's team didn't win the robot competition . But they had a great time working on their Robotics merit badges  at the 2011 Advance Camp in Antioch , Calif . Advance Camp is held the last Saturday in September at the Contra Costa County Fairgrounds in Antioch, Calif.Nearly 1,500 Scouts attended in 2011 and worked on different merit badges .Scouts choose from more than 50 merit -badge classes taught by counselors  .They can earn merit badges from Fingerprinting to Nuclear Science to Swimming .Robotics is the most popular class . First , one of the counselors talked to Matthew and the other Scouts in his Robotic class about the many different uses for robots . "I learned how advanced it really is ," Matthew says . "Robots are used in medicine and industry ." After the talk , the Scouts were divided into five-person teams . Each team was required to build a basic robot . The next step was programming the tiny computer in the robot so it would make the right moves once it was in the ring . "We programmed our robot so its arm was moving all the time ," Matthew says . "That way , it would knock the other robot over." . That's when they discovered the arm on their robot was too long . As a result , their robot knocked itself over before it could fight with any other robots . "It was a learning experience ," Matthew says . "You have to think ahead." The author writes this text mainly to   _   . A) explain what Scouts do B) introduce an interesting camp C) advertise a robot competition D) encourage Scouts to learn technology
B
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The Beijing Youth Daily on Thursday called attention to the struggles of traditional operas in China. The newspaper said the number of unique traditional Chinese opera styles had decreased to 286 from 368 in 1959, with three disappearing every two years on average. Altogether, 74 opera styles had only one troupe left, and most were at the risk of fading away. Xie Boliang, a professor at the National Academy of Chinese Theatre Arts, said, "It is well known that people should be held accountable for soil erosion, but why do we feel at ease when traditional operas fade away?" Overwhelmed by modern culture and entertainment such as movies, TV programs and pop music, traditional Chinese operas have been severely marginalized. Despite being included on the state-level Intangible Cultural Heritage list, some operas still have no place to perform. Because of the market slump   and low salaries, more traditional Chinese opera practitioners are finding other work, as are many directors and playwrights. Sun Jiazheng, chairman of the China Federation of Literary and Art Circles, said traditional operas are important carriers of Chinese culture, and should be preserved. The State Council issued a circular in July calling for the promotion and protection of traditional Chinese operas, saying that it would allocate financial support and extend preferential policies to opera troupes and schools. Many directors and playwrights find other jobs because   _  . A) Chinese operas are booming B) they do not enjoy their work any more C) the market is not promising and they get paid poorly D) they are not considered as important inheritors of Chinese culture
C
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A new study says one part of the human brain may become smaller as the result of a condition known as jet lag. Jet lag results from flying long distances in an airplane. Jet lag interferes with a person's normal times for sleeping and waking. People with jet lag may feel extremely tired for several days. They also may have problems thinking clearly and remembering. Kwangwook Cho is a researcher at the University of Bristol in Britain. He reported the findings of his jet lag study in the publication Nature Neuroscience. The study involved twenty young women who worked for international airlines. The women had served passengers on airplanes for five years. These flight attendants flew across many countries and at least seven time zones. In the study, the flight attendants had different amounts of time to recover from jet lag. Half the women spent five days or fewer in their home areas between long flights. The other half spent more than fourteen days in their home areas. Mister Cho took some fluid from the women's mouths to measure levels of a hormone that increases during stress. He tested them to see if they could remember where black spots appeared on a computer screen. And he took pictures of their brains using magnetic resonance imaging. This is a way to measure the size of the brain's temporal lobes. It was found that the women who had less time between flights had smaller right temporal lobes. This area of the brain deals with recognizing and remembering what is seen. The same group performed worse and had slower reaction times on the visual memory test. And their saliva samples showed higher levels of stress hormones. Mister Cho says he believes the brain needs at least ten days to recover after a long trip. He says airline workers told him their ability to remember got worse after working on planes for about four years. Other studies have shown that increased feelings of stress can cause a loss of cells in the part of the brain that controls memory. Scientists say more tests are needed to study the... According to the text, jet lag   _  . A) can cause difficulties in speaking B) can make people feel tired for a few weeks C) is the illness only found in people who work on the airplanes D) can be caused by flying over several time zones in an airplane
D
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A man once said how useless it was to put advertisements in the newspaper. "Last week, " he said,  "my umbrella was stolen from a London church. As it was a present,  I spent twice its worth in advertising,  but didn't get it back. " "How did you write your advertisement? " asked one of the listeners,  a merchant. "Here it is, " said the man,  taking out of his pocket a slip cut from a newspaper. The other man took it and read,  "Lost from the City Church last Sunday evening,  a black silk umbrella. The gentleman who finds it will receive ten shillings on leaving it at No. 10 Broad Street. " "Now, " said the merchant,  "I often advertise,  and find that it pays me well. But the way in which an advertisement is expressed is of extreme importance. Let us try for your umbrella again,  and if it fails,  I'll buy you a new one. " The merchant then took a slip of paper out of his pocket and wrote:  "If the man who was seen to take an umbrella from the City Church last Sunday evening doesn't wish to get into trouble,  he will return the umbrella to No. 10 Broad Street. He is well known. " This appeared in the newspaper,  and on the following morning,  the man was astonished when he opened the front door. In the doorway lay at least twelve umbrellas of all sizes and colors,  and his own was among them. Many of them had notes fastened to them saying that they had been taken by mistake,  and begging the loser not to say anything about the matter. The merchant suggested that the man should  _   . A) buy a new umbrella B) go on looking for his umbrella C) write another and better advertisement D) report the police

C
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