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If you're worried that too much“screen time”could badly influence your child's intelligence，new research suggests you might be right.By analyzing the data gathered from over 4，500 U．S.kids aged between 8 and 11 in 2016 and 2017，Jeremy Walsh，a postdoctoral fellow with the CHEO Research Institute in Ottawa，found that too much“screen time” could harm your child's intelligence.
Kids with the sharpest intellect spent less than two hours a day on their cell phones, tablets and computers coupled with 9 to 11 hours of sleep and at least an hour of physical activity.Too much screen time could affect kids' ability to focus，especially if they are switching between apps on a device or between different screens at the same time，Walsh suggested.“One leading theory is that much time on screens is spent using multiple apps or devices at once，”he said.“This can interfere with a child's ability to focus on and keep interested in a task.It can damage the building blocks for good cognition(认知)．”
“Sleep is important for brain development，since that's when the brain reorganizes itself and grows，”Walsh added.Besides，exercise has been shown to increase blood flow to the brain and oxygenation of brain tissues, and increase the connectivity of networks in the brain.Too much screen time could lead to a“cascade”effect(级联效应) where kids don't get enough sleep and then are less active during the day.“You can see how this would have an impact on brain health，”Walsh said.
What should parents do？Walsh advised them to set firm rules about the use of screens including how long children are using the screens，the kinds of apps they are using and how many screens they are using at once.Concerned parents also should preview games or apps before letting their child play，seek out more interactive(交互的) options that engage the child's mind，use parental controls to block or filter the content and limit the screen time.
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【参考范文】
New research has found that excessive“screen time” may negatively affect children's intelligence.(要点1)It prevents children from focusing and staying interested，thus restricting their cognitive development.(要点2)Also，it results in inadequate sleep and lack of physical activity，which can do harm to the brain health.(要点3)Accordingly，parents are advised to establish strict regulations concerning the use of screens，monitor the content and limit the screen time.(要点4)
