空白处缺什么介词？八年级 帮帮我????

1.They are going to hike to the top of a
2.On the holidays,trains,buses and planes are all very busy.
3.Last Saturday,everything was ready for Ann's party.
4.Very often they gave a concert in the open air.

of
on
for
in

of
On
for
in

1.......of
2.......during
3.......for
4.......in