教室里贴有四幅图幅大小相同的地图，按比例尺由大到小排列正确的是(  )

  ①世界地图  ②中国地图  ③浙江地图  ④杭州地图

已知$\cos \left(\alpha -\beta \right)=-\frac{4}{5}$$\cos \left(\alpha +\beta \right)=\frac{4}{5}$，且$\left(\alpha -\beta \right)\in \left(\frac{\pi }{2},\pi \right),\left(\alpha +\beta \right)\in \left(\frac{3\pi }{2},2\pi \right)$，则$\cos 2\alpha$=（     ）

当x=2时，代数式ax³+bx+1的值为6，那么当x=-2时，这个代数式的值是（    ）

阅读理解。

    Amy and Sarah are good friends. They are from America. They like winter in America because there are many activities in winter. They can make a snowman,go fishing and go skiing with many friends. There are two festivals (节目) in winter. They're Christmas Day and Thanksgiving. Amy and Sarah are very happy. But they're in Beijing now. They like winter in Beijing, too. Because It's beautiful. It's windy and cold. They're going to visit the Great Wall, so they're very happy.