Underline the correct preposition to complete the sentences

VI. Underline the correct preposition to complete the sentences. 
1. What will you do on/in Monday?
 2. It is often rainy at/in autumn. 
3. What did you do in/at the afternoon?
 4. I often get up on/at 7 o'clock. 
5. Flowers are beautiful at/in spring, 
6. I watched a new film on/at midnight. 
7. My brother's birthday is at/on 16" December 
8. Sam watched football on/in the evening. 
9. Do you get presents on/in Christmas Day? 
10. We had lunch at/on noon. 
11. My father was born on/in 1970. 
12. It is very cold at/in winter,
 13. Will you go to the club on/in Friday morning?
 14. What did you do at/in Easter? 
15. We'll go to a picnic in/on Saturday.