If a diver surfaces too quickly, he may suffer the bends. Nitrogen dissolved in his blood is suddenly liberated by the reduction of pressure. The consequence, if the bubbles accumulate in a joint, is sharp pain and a bent body -- thus the name. If the bubbles form in his lungs or brain, the consequence can be death. Other air-breathing animals also suffer this decompression sickness if they surface too fast: whales, for example. And so, long ago, did ichthyosaurs . That these ancient sea-animals got the bends can be seen from their bones. If bubbles of nitrogen form inside the bone they can cut off its blood supply. This kills the cells in the bone, and consequently weakens it, sometimes to the point of collapse. Fossil bones that have caved in on themselves are thus a sign that the animal once had the bends. Bruce Rothschild of the University of Kansas knew all this when he began a suty of ichthyosaurs bones to find out how widespread the problem was in the past. What he particularly wanted to investigate was how ichthyosaurs adapted to the problem of decompession over the 150 milllion years. To this end, he and his colleagues traveled the world's natural-history museums, looking at hundreds of ichthyosaurs from the Trassic period and from the later Jurassic and Cretaceous periods. When he started, he assumed that signs of the bends would be rarer in younger fossils, reflecting their gradual evolution of measures to deal with decompression. Instead, he was astonished to discover the opposite. More than 15% of Jurassic and Cretaceous ichthyosaurs had suffered the bends before the died, but not a single Trassic specimen showed evidence of that sort of injury. If ichthyosaurs did evolve an anti-decompression means, they clearly did so quickly -- and, most strangly, they lost it afterwards. But that is not what Dr Rothchild thinks happened. He suspects it was evolution in other animals that caused the change. Whales that suffer the bends often do so because they have sufaced to escape a predator such... Rothchild might have concluded that ichthyosaurs _ . A) failed to evole an anti-decompression means B) grdually developed measures against the bends C) died out because of large sharks and crocodiles D) evoled an anti-decompression means but soon lost it
A
Haikou--A shark was killed after being dragged to shore at Yalong Berth beach in Sanya, South China's Hainan Province, on Sunday afternoon. It was the first time a shark had been caught in the beach area, a popular tourist site in Hainan. Local fishermen said they caught the 3-meter-long, l-ton shark by chance when they were fishing in sea water 1,000 metres deep near the beach. Police temporarily protected the shark while oceanographers decided whether it was a species belonging to State protection. Fishermen later killed and sold the shark after oceanographers _ that it was a whale shark and therefore not under State protection. The shark was believed to have drifted into the area from the deep sea due to strong waves caused last week by Typhoon Imbudo.It had no open injuries but experts said they believed it suffered from internal bleeding. Local police officer Fu Chenggeng said beachgoers should not feel threatened by sharks because the fish never attack human beings on their own initiative.Fu said he had never heard of any shark attacks at the Sanya beach since he first started work there eight years ago. However, police said they will improve the security system to safeguard tourists' safety on the beach. A possible title of the article should be _ . A) Tourists in Danger B) Killing Whale Shark C) Shark Caught in Beach Area D) Whale Shark in Danger
C
Q: BEIJING, July 21-More and more parents in Shanghai have found that their children are forgetting how to use Shanghai dialect to express themselves, according to a report in the city's Jiefang Daily on July 11, and some have begun forcing them to speak it at home. Language experts say that the promotion of Putonghua, and the large number of non-Shanghainese setting down in the city have meant that the local dialect has lost its previous high social status, according to the report. They have urged that the dialect be protected alongside Putonghua (also known as Mandarin), the nation's common tongue that has been systematically promoted since new China was founded in 1949. In their opinion, dialects carry and preserve local culture . They say that a dialect is not only a linguistic tool. But is also like a person's "birthmark" and part of their local identity and feeling of belonging. They recommended that TV and radio stations set up channels and programs using dialects , and that schools offer selective courses in which the dialects are taught. The experts also suggested that dialect be protected while maintaining high standards of Putonghua and a multicultural environment in the city. Why should local dialects be protected ? A) It is China's policy. B) Putonghua is not practical. C) Local dialects carry and preserve local culture. D) More and more parents in Shanghai have asked to do so.
A: C
Q: Women are friendly. But men are more competitive. Why? Researchers have found it's all down to the hormone oxytocin . Although known as the love hormone, it affects the sexes differently. "Women tend to be social in their behavior. They often share with others. But men tend to be competitive. They are trying to improve their social status," said Professor Ryan. Generally, people believe that the hormone exytocin is let out in our body in various social situations and our body creates a large amount of it during positive social interaction such as falling in love or giving birth. But in a previous experiment Professor Ryan found that the hormone is also let out in our body during negative social interactions such as envy. Further researches showed that in men the hormone oxytocin improves the ability to recognize competitive relationships, but in women it raises the ability to recognize friendship. Professor Ryan's recent experiment used 62 men and women aged 20 to 37. Half of the participants received oxytocin. The other half received placebo . [( )] [( :Love my Dog.)] After a week, the two groups switched with participants. They went through the same procedure with the other material. Following each treatment, they were shown some video pictures with different social interactions. Then they were asked to analyze the relationships by answering some questions. The questions were about telling friendship from competition. And their answers should be based on gestures, body language and facial expressions. The results indicated that, after treatment with oxytocin, men's ability to correctly recognize competitive relationships improved, but in women it was the ability to correctly recognize friendship that got better. Professor Ryan thus concluded: "Our experiment proves that the hormone oxytocin can raise people's abilities to better distinguish different social interactions. And the behavior differences between men and women are caused by biological factor that are mainly hormonal." What can we learn from Professor Ryan's previous experiment? A) Oxytocin affects our behavior in a different way. B) Our body lets out oxytocin when we are deep in love. C) Our body produces oxytocin when we feel unhappy about others' success. D) Oxytocin improves our abilities to understand people's behavior differences.
A: A