题目

阅读理解     Scientists have created the world's first living, self-healing robots using stem cells (干细胞) from frogs. Named xenobots after the African clawed frog from which they take their stem cells, the ''machines'' are less than a millimeter wide — small enough to travel inside human bodies. They can walk and swim, survive for weeks without food, and work together in groups. "These are entirely new life forms," said the University of Vermont, which conducted the research with Tufts University's Allen Discovery Center.     The researchers removed living stem cells from frog embryos (胚胎), and left them to hatch. Then, the cells were cut and reshaped into specific ''body forms" designed by a supercomputer — forms ''never seen in nature", according to a news release from the University of Vermont.     Xenobots even have regenerative abilities. When the scientists sliced into one robot, it healed by itself and kept moving. They don't look like traditional robots - they have no shiny clothing or robotic arms. Instead, they look more like a tiny drop of moving pink flesh. The researchers say this is deliberate — this ''biological machine'' can achieve things typical robots of steel and plastic cannot. ''Traditional robots degrade over time and can produce harmful ecological and health side effects," researchers said in the study. "As biological machines, xenobots are more environmentally friendly and safer for human health.''     According to the researchers, these robots could be used to clean up radioactive waste, collect microplastics in the oceans, or even carry medicine inside human bodies. Aside from these immediate practical tasks, they could also help researchers to learn more about cell biology - opening the doors to future advancement in human health and longevity. This sounds like something from a sci-fi movie. Some people even voiced their concern that humans might be taken control of by those xenobots. However, the researchers in the study say there is no need for alarm. They can't reproduce or evolve (进化). （1） What is this passage mainly about? A . The advantages of a medical robot. B . The application of robots in biology. C . The general introduction of a living robot. D . The medical value of African clawed frogs. （2） The underlined word ''regenerative'' in Paragraph 3 probably means "________". A . living longer B . growing again C . replacing old cells D . defending against attacks （3） What can we know about xenobots? A . They can do everything that traditional robots can. B . They can break up steel and plastic while degrading. C . They are able to cure people of all kinds of diseases. D . They are harmless to the environment and human health. （4） What is the researchers' attitude to the development of xenobots? A . Doubtful. B . Positive. C . Cautious. D . Casual. 答案： C B D B

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