“Hello, everyone! Welcome to Tiangong Class.” With this greeting, a special lecture began _____ Tiangong space station on Dec 9.

Lasting for about _____ hour, the space lecture was broadcast live to the students. “Three astronauts from the Shenzhou XIII crew — Zhai Zhigang, Wang Yaping and Ye Guangfu — hosted the lecture, showing _____ there and doing some interesting experiments that can only _____ in space. This is the second live space lecture in China. In 2013, with the help of other Sheinzhou X crew members, Wang decided _____ a speech to over sixty _____ schoolchildren across China.

Compared with the class eight years ago, this year’s space lecture is greatly different. According to Pang Zhihao, a Beijing-based space expert, the “classroom” is much _____. Instead of Tiangong I experimental module, this year Wang delivered the space lecture in the Tianhe space core module (核心舱) which is the biggest spacecraft developed by China.

Eight years ago, Wang _____ students the laws of physics and focused on the interesting phenomenon (现象) of weightlessness (失重) in space. _____ this year, biology was added. The astronauts compared the growth and shape of cells in artificial gravity (人工重力) and zero gravity in order to study their changing rules and mechanisms (机械装置).

“The spirit of science in the youth is an important driver of the progress of mankind,” Zhou Jianping, designer-in-chief of China’s manned space program; added. “Space activities can help _____ build the spirit of pursuing science and facing challenges.”