【简答题】A.They studied variations in the appearance of the parent stars. B.They were able to see the planets with a telescope. C.They compared the parent stars to the Sun. D.They sent astronauts on a mission ...
【简答题】A.They studied variations in the appearance Of' the parent stars. B.They were able to see the planets with a telescope. C.They compared the parent stars to the Sun. D.They sent astronauts on a mission...