计算: 3x−1 + x−31−x2
问:小明在第____步开始出错,小红在第____步开始出错(写出序号即可);请你给出正确解答过程.
“冷战消失了……为具有更加多元化特点的社会开启了大门。”据此可知,当今世界政治格局呈现出的局面是( )
All the students are advised to keep a ____ (balance) diet for their health.