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①尊重各民族的语言文字 ②尊重各民族的宗教信仰、风俗习惯 ③与少数民族要尽可能的减少交往 ④帮助少数民族地区发展经济
看图列示计算。
You'd better ask a ______, such as your aunt or sister, to look after your children while you are away.
设变量x,y满足约束条件 {2x+y≥0x+2y−2≥0x≤0y≤3 ,则目标函数z=x+y的最大值为( )