user: Q: Read the article and select the best answer. Article: The Touchstone When the great library of Alexandria burned, the story goes, one book was saved. But it was not a valuable book, and so a poor man, who could read little, bought it for very little money. The book wasn't very interesting, but between its pages there was something very interesting indeed. It was a thin strip of vellum on which was written the secret of the "Touchstone"! The touchstone was a small pebble that could turn any common metal into pure gold. The writing explained that it was lying among thousands and thousands of other pebbles that looked exactly like it. But the secret was this: The real stone would feel warm, while ordinary pebbles are cold. So the man sold his few belongings, bought some simple supplies, camped on the seashore, and began testing pebbles. He knew that if he picked up ordinary pebbles and threw them down again because they were cold, he might pick up the same pebble hundreds of times. So, when he felt one that was cold, he threw it into the sea. He spent a whole day doing this but none of them was the touchstone. Yet he went on and on this way. Pick up a pebble. Cold, throw it into the sea. Pick up another. Throw it into the sea. Pick up another. Throw it into the sea. The days continued over a long period of time. One day, however, about mid-afternoon, he picked up a pebble and it was warm. He threw it into the sea before he realized what he had done. He had formed such a strong habit of throwing each pebble into the sea that when the one he wanted came along he still threw it away. So it is with opportunity. Unless we are careful, it's easy to fail to recognize an opportunity when it is in hand and it's just as easy to throw it away. Question: The man bought the book because    _   . Options: A: he wanted to read it B: it was very interesting C: there was a secret in the book D: he wanted to find the touchstone
A: A


Q: Read the article and select the best answer. Article: We often see wind-horse flags in Tibetan areas. They are long cloths on which pictures of horses and scriptures are printed. People often put these flags on top of houses, or leave them where a vehicle accident happened. They prevent evil spirits from injuring people again. A wind-horse flag can be white, yellow, red, green or blue. These five colors symbolize the five elements that form the world; earth, water, fire, wind and sky. Another explanations that red is the sun, green is the grassland, yellow is the earth, blue is the sky, and white is the cloud. The wind-horse flag originated with a monk who obtained a scripture from India. When he crossed a river, he carelessly dropped the scripture into the water. He quickly saved the scripture and spread it out on a big rock to dry as he sat in meditation . Suddenly violent thunder sounded like drums. The monk felt liberated from all of his sadness, and when he opened his eyes he saw that the scripture had been blown into the sky by a strong wind. Finally, he went straight to heaven. In order to honor the spirit of the monk and the Buddhist scripture, people printed the scripture on a piece of cloth and hung it up between the sky and the earth as though the scripture was flying in the sky. We also know why people put the wind-horse flag on the top of mountains and houses. The Tibetan ancestors had a very great idea about chanting scripture. They thought people not only could chant scripture, but also the five elements. The wind-home flag is a good example of how they use the wind to blow the flag, which means that the wind also chants scripture. Question: What happened when the monk meditated? Options: A: He felt very sad about his mistake. B: The scripture was blown into the sky. C: He was punished by the gods. D: Many wind-house flags were flying.
A: B


Q: Read the article and select the best answer. Article: Chinese scientists have found a new way to use cells found in human urine  that could aid in the treatment of a range of nerve disorders.That is a new technique for reprogramming cells in human urine into nerve progenitor cells  that can grow into multi-functional nerve and brain cells. The technique is expected to be used in the study and treatment of nerve disorders such as Parkinson's disease, Alzheimer's disease and other nerve disorders. Pei Duanqing, a professor at Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, said his research team has combined an episomal system to deliver reprogramming factors with a chemically defined culture medium to reprogram kidney epithelial  cells in urine into NPCs. These NPCs, normally only found in the human brain, were later proven to be transgene-free and self-renewing, he said. "These nerve and brain cells can survive for up to one month when transplanted into the brain of a newborn rat," said Pei. "My team is working hard to understand why our experimental condition allowed the urine cells to become NPCs, because we want to improve the technique and make it more efficient". Scientists have long searched to treat and study neural disorders by obtaining and transplanting neural stem cells. However, the previous method of getting and using cells from either fetal  or adult human tissue remains challenging due to ethical concerns and immune system rejections, he said. Pei hopes the discovery will be used to generate NPCs from patients with nerve disorders such as Parkinson's disease. "These NPCs from patients may help us discover new drugs for these diseases." "It is a remarkable advance in the stem cell field. The results and methods obtained from this study will be of great value and significance to the field, " said Fred Gage,a professor with the Salk Institute for Biological Studies. Question: What is the challenge of making NPCs in the previous method? Options: A: The ethical comcerns and immune system refusal B: The difificulties in getting cells from human. C: The under-developed techniques in medical science. D: The lack of financial support from the government.


assistant: A: A