2011年6月大学英语四级真题Questions 47 to 56 are based on the following passage.The popular notion that older people need less sleep than younger adults is a myth, scientists said yesterday.While elderly people _47_ to sleep for fewer hours than they did when they were younger, this has a(n) _48_ effect on their brains performance and they would benefit from getting more, according to research.Sean Drummond, a. psychiatrist (心理医生) at the University of California, San Diego, said older people a
