句型转换。
The ______ of her children playing in the yard is always remembered by the mother.
根据氢原子能级图（如图）可判断（ ）
①dog____ A.
②elephant ____ B.
③girl ____ C.
若抛物线y2=x上一点P到准线的距离等于它到顶点的距离，则点P的坐标为（ ）
