互动封闭仿真课堂1、智能交互 2、电子板书式视频教学 3、5分钟一次互动问答 4、封闭课堂
The following are some facts and figures about the closing ceremony of the Beijing Olympic Games， held here on Sunday night.
The closing ceremony is held in the National Stadium， also known as the Bird‘s Nest， in the Olympic Green in northern Beijing.
The stadium was jointly designed by Herzog & de Meuron Design Office， and China Architecture Design & Research Group and ARUP. Its construction began on December 24， 2003， and completed on June 30， 2008.
The stadium’s seating capacity is 91，000， including 11，000 temporary seats. The floor space is 258，000 square meters.
The tower， consisting of five stories of elevation structure， is stretchable. Its maximum height is 20.7 meters and maximum load is 20 tons.
Design and construction of the tower lasted a year and 30 tons of steel was used.