Questions 6 are based on the following news. At the end of the news item, you will be given 20 seconds to answer the questions. Now listen to the news.
What is the news item mainly about? ()
A.A problem in the cooling system was solved.
B.A 350-kilogram ammonia pump was removed.
C.US. astronauts made three space walks.
D.An international space station was set up.