阅读理解。 In some children who go blind, certain parts of the brain that normally control vision appear to switch jobs and focus instead on sound, a new study has found. The study, by researchers at the University of Montreal, involved 7 s who could see and 12 s who had lost their vision when they were children. Each participant sat in a room with 16 loudspeakers at different locations. The room was designed so that there were no echoes(回音). During the experiment, the speakers irregularly produced sounds. Participants had to point to where the sounds were coming from. Meanwhile, the researchers monitored blood flow in the brains of the participants to see which brain structures were working during the task. The results showed that five of the blind participants were very good at pointing to where sounds were coming from. In these people, blood flow increased in the visual cortex(大脑皮层)-an area at the back of the right side of the brain. This part of the brain is usually associated with vision. The other seven blind participants showed no increase in activity in the visual cortex. These people didn't do very well at picking out where sounds were coming from. Now, the researchers are looking at whether these people have gained an enhanced sense of touch instead of sound to replace their lost vision. The scientists say that their study shows how adaptable parts of the brain can be. 1.  The purpose of the experiment described in the passage is to find whether_____. A. blind children can regain their sight B. blind people have a better sense of sound C. the sense of touch is better among blind people D. blood flow in the brains of blind people is slower 2. The participants of the experiment were asked _____. A. to tell the difference between 16 sounds B. to take down the time each sound lasted C. to identify the direction the sound came from D. to detect the number of the loudspeakers 3. During the experiment, blood flow in the brains of the participants was measured in order to _____. A. learn about the way they react to echoes B. look for the way of enhancing hearing ability C. find which parts of the brain were functioning D. expose the relationship between seeing and touching 4. Which of the following statements best summarizes the main idea of the passage? A. Most blind people have a well-developed sense of touch. B. People go blind because of the breakdown of their visual cortex. C. Most blind people have a better sense of sound than normal people. D. Human brains can adjust themselves after the loss of a certain function.