史载,宋太祖某日闷闷不乐,有人问他原因,他说:“尔谓帝王可容易行事耶……偶有误失,史官必书之,我所以不乐也。”此事反映了( )
—Don't do any other things while you are having a class. So please _______ your MP3.
—Sorry, I will do it right now.
两圆半径R、r分别是方程x2-3x+2=0的两根,且圆心距d=3,则两圆的位置关系是( )