They ____（种植）some vegetables yesterday. My uncle has been to

They ____（种植）some vegetables yesterday. My uncle has been to America ____（两次）.
They ____（种植）some vegetables yesterday.
My uncle has been to America ____（两次）.
It's bad for your eyes because the ____（光线）is very poor.
Our solar system is only a ____（部分）of the galaxy.
Are we ____（孤单的）in the universe?
The light has travelled several years to ____（到达）us.
How many ____（行星）are there going around the Sun?