Surfing the Internet can help open students' eyes and get more knowledge. As a teacher, I encourage my students to use the Internet. In class those students who surf the Internet understand lessons better than the others. Besides, people can use the Internet to write letters or stories and send emails. Many students communicate with their friends online. You can also make friends by chatting on QQ. It's cheaper than calling somebody far away and it's much quicker. Nearly one third of young people surf the Internet for fun. They like to listen to music, watch films, and go to their favorite stars' websites. But can the Internet cause problems? Some of my students who used to study well at school are now failing exams. Because they spend a lot of time playing computer games.

画出下左图中经透镜折射后的光线.

《大国崛起》解说词中指出，l7世纪某国“在历史性的转变中抢了先机，已经率先到达了现代文明的入口处……在下两个世纪里，它将傲视全球”。该国能够傲视全球的政治基础是（　　）