填空题 A everything
B a great success
C a tremendous failure
D nothing
E mangy firsts
F quite possible

填空题 Mir enhanced the confidence in the scientists that human living in space for a long time was ______.

填空题 In Mir, the US astronauts created ______.

填空题 When we think of Mir in terms of its achievements, its setbacks are ______.

填空题 The writer tends to think that Mir was ______.