Fill in the prepositions: on,in,at,under,of.

1.The school year begins ___ September.
2. It's a habit to exchange gifts Christmas.
3. I am tired doing the same thing every day.
4. The old man sat ___ the tree to have a rest.
5. Pupils have no classes ___ weekends.
6. They eat their traditional meal ___ Christmas Day.
7. We don't have much free time ___ weekdays.