某种游戏中,黑、个“电子狗”从棱长为1的正方体ABCD-A 1 B 1 C 1 D 1 的顶点A出发沿棱向前爬行,每爬完一条棱称为“爬完一段”.黑“电子狗”爬行的路线是AA 1 →A 1 D 1 →…,黄“电子狗”爬行的路线是AB→BB 1 →…,它们都遵循如下规则:所爬行的第i+2段与第i段所在直线必须是异面直线(其中i是正整数).设黑“电子狗”爬完2008段、黄“电子狗”爬完2009各自停止在正方体的某个顶点处,这时黑、黄“电子狗”间的距离是______.
【简答题】Section A Composition [35 min] Nowadays people are becoming increasingly aware of the importance of health. And they have different ways to stay healthy. For example, some exercise every day; others t...