Sara is thrilled to begin second grade. She's one of the bigger kids now and is looking forward to all the big-kid stuff she'll get to do, like being the first one to be on the swing-set playground before the school day starts. She decides that Marcus, one of the littler kids in her class, doesn't need to swing, so she pushes him off the swing. Marcus isn't happy. Their classmate, Grace, gives up her swing so Marcus can enjoy it too. Immediately,...