如图，长为4cm、宽为3cm的长方形木板在桌面上做无滑动的翻滚（顺时针方向），木板上点A的位置变化为A→A₁→A₂，其中第二次翻滚被桌面上一小木块挡住，使木板与桌面成30°角，则点A翻滚到A₂位置时共走过的路径长为（   ）

下面一组数中的素数是(   )

    What brings a nation together? Of the four choices — shared values, language, history, and religion, it's shared values. In our latest poll (民意调査), seven out of 16 countries chose values as the greatest factor (因索）bringing a nation together, and six preferred language. Both choices scored high in the poll, suggesting that our values and how we express them are closely linked Still, history was not forgotten in some countries, particularly in Mexico and Russia. Even Canada and the United States chose national histories as the second-most important factor uniting their people. The biggest surprise? Not one country picked religion as its top choice.

从图在我国的地形类型来看，所占比例最大的甲类型是：

翻译下列句子。