a) Astronauts are trained to undergo extreme conditions ... can be dangerous.
b) The NASA engineers ... were interviewed are really gifted.
c) The science-fiction writers ... we admire shape our visions on science.
d) The planets ... human colonisation could be possible have been depicted in sci-fi.
e) The centuries ... space travel was impossible are over.
f) The place ... Armstrong set foot on the Moon can be seen from the Earth.
