The amount of time children spend in institutional care（机构式照顾）may affect how their brains develop. That’s the conclusion of a new study carried out by researchers at the University of Wisconsin, Harvard Medical School and the University of Minnesota. The study is published in Child Development in the journal’s January/ February 2010 issue. To learn how the lack of care and material needs that institutionalized children often experience affect brain development, the researchers looked at 132 8- and 9-year-olds. Some of them were adopted into U.S. homes after spending at least a year and three quarters of their lives in institutions in Asia, Latin America, Russia and Eastern Europe, and Africa. Others were adopted by the time they were 8 months old into U.S. homes from foster care（寄养）in Asia and Latin America; most of these children had spent no time in institutional care, while some had spent a month or two in institutions prior to foster placement. On average, the internationally adopted children had been living with their families for more than 6 years. These children were compared to a group of American children raised in their birth families. Children adopted early from foster care didn't differ from children raised in their birth families in the United States. Children adopted from institutional care performed worse than those raised in families on tests measuring visual memory and attention, learning visual information, and impulse （冲动）control. Yet these children performed at developmentally appropriate levels on tests involving sequencing and planning. The take-home message: Children make tremendous advances in cognitive（认知的） functioning once they reach their adoptive families, but the early impact on their brains' development is difficult to change completely. "We identified basic learning processes that are affected by early institutionalization," notes Seth Pollak, professor of psychology and pediatrics at the University of Wisconsin, who was the study's lead author. "Policies that speed the time in which children can be removed from institutionalized care so they can develop within family contexts should be implemented to decrease the likelihood of learning problems later in children's lives." 67．The passage is mainly written to___________. A．compare two childcare systems B．criticize the institutional childcare C．present a new research finding D．introduce the basic learning process 68．Children have their brain development affected in institutional care because__________. A．they suffer form poor living conditions B．they spend too much time learning C．they don’t have staying there D．they are neither physically nor mentally satisfied 69．Compared with home-raised children, institutionalized children didn’t do as well in tasks like__________. A．thinking in pictures and self-control B．working in teams and self-expression C．putting things in order and self-defense D．adapting to the environment and self-panning. 70．It can be concluded form the passage that__________. A．the United States is a good place for children’s all-round development B．a perfect family is beneficial to children’s all-round development C．children in institutional care can hardly achieve anything great D．nothing has been done to help children in institutional care