LiRuyan,13yearsold,didsomethingspeciallastsummerwithhis...
问题详情：LiRuyan,13yearsold,didsomethingspeciallastsummerwithhisclassmatesinShanghai.Theyworkedingroupswithtrafficpoliceatdifferentcrossroadsinthecity.Holdingsmallredflags,thestudentshelpedkeeporderand...