Go outside om a sunny day and look at/on your shadow! Early in/at the morning and late in the afternoon, it is long. At lunchtime, it has/is very short. This is because the Earthmoves around the sun and the sun is in a different place in/on the sky and different times of the day. Sundials use shadows to tell the time. They have/are the oldest way to tell the time!

1.at
2.in
3.is.
4.in
5.are