文档介绍：北京地区***本科学士学位英语统一考试
Part I prehension Directions: There are three passages in this passage is followed by some questions or unfinished each of them there are four choices marked A, B, C and D. You should decide on the best choice and blacken the corresponding letter on the Answer sheet.
Spending 50 minutes with a cell phone close to your ear is enough to change brain cell activity in the part of the brain closest to the antenna (天线).But whether that causes any harm is not clear, scientists at the National Institute of Health said at a conference last month, adding that the study will not likely settle concerns of a link between cell phones and brain cancer."What we showed is glucose(葡萄糖) metabolism(代谢) (a sign of brain activity) increases in the brain in people who were exposed to a cell phone in the area closest to the antenna," said Volkow of the NIH, whose study was published in the Journal of the American Medical Association.(76) The study was meant to examine how the brain reacts to ic fields caused
by wireless phone signals.
Volkow said she was surprised that the weak ic radiation(电磁辐射) from cell
phones could affect brain activity, but she said the findings do not shed any light on whether cell
phones cause cancer."This study does not in any way indicate the study does is to show the human brain is sensitive to ic radiation from cell phone exposures." Use of the devices has increased dramatically since they were introduced in the early 1980s, with about 5 billion cell phones now in use worldwide.
Some studies have linked cell phone exposure to an increased risk of brain cancers, but a large study by the World anization did not offer a clear answer to ' s team studied 47 people who had their brain examined while a cell phone was turned on for 50 minutes and another while the phone was turned there was plete change in brain metabolism,
they found a 7 percent increase in brain metabol