摘要
Three Chinese astronauts'wonderful voices re⁃sounded in the ground classrooms as the schoolchil⁃dren listened with attention.This was no ordinary course.It was delivered some 400 km above the Earth in China's space station by Zhai Zhigang,Wang Yap⁃ing and Ye Guangfu.A total of 1,420 students at⁃tended the lecture from five classrooms across China.
