Thelongerateenagerspendsusingelectronicdevicessuchascom...
問題詳情：Thelongerateenagerspendsusingelectronicdevicessuchascomputersandsmartphones，theworsetheirsleepwillbe，astudyofnearly10，00016-to19-year-oldssuggests．Morethantwohoursofscreentimeafterschoolwasstrongl...