“Hello, everyone! Welcome to Tiangong Class.” With this greeting,     1     special lecture began on Tiangong space station about 400 kilometers above Earth on Dec 9, 2021. Lasting for about an hour, the space lecture     2    (broadcast)live to millions of students. Three astronauts from the Shenzhou XIII crew-Zhai Zhigang, Wang Yaping and Ye Guangfu-hosted the lecture, demonstrating     3     they live and work on the space station and conducting some interesting experiments that can only     4    (do)in space.

This is the second live space lecture in China. In 2013, with the     5    (assist)of two other Shenzhou X crew members, Wang delivered the country’s first live space lecture to over 60 million schoolchildren across China. With the help of China’s Tianlian relay satellites, the transmission speed has been highly increased and the whole live broadcast has run     6    (smooth). According to Xinhua, these changes show that Chinese aerospace industry     7    (make)great strides in the past eight years.

Along     8     the technological progress, this year’s space lecture discussed more disciplines of science. Eight years ago, Wang showed students the laws of physics and focused on the interesting phenomenon of weightlessness in space. But this year, biology was added. The astronauts compared the growth and shape of cells in artificial gravity and zero gravity     9    (study)their changing rules and mechanisms.

    10     these space lectures showed various topics, the aim behind the lectures has never changed. According to China Daily, the space lectures aim to “spread knowledge about manned spaceflights and spark enthusiasm for science among young people”.