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.

面对H7N9禽流感，政府有关部门在首例病例确诊后，立即通过电视、网络等媒体发布详细疫情信息，并及时跟进通报疫情变化情况及防治方案，使政府和社会形成合力，共同防治禽流感。这些做法能够（  ）

①提高行政效率，体现政府威信　 ②加强社会监督，促进廉政建设

③增强信息透明，保障公民权利　 ④消除社会矛盾，维护国家稳定

若cos( $\frac{\pi }{4}$ –α)= $\frac{3}{5}$ ，则sin 2α=(  )