Write in, at or on.

1. in the morning; 2. on Tuesday; 3. in the afternoon; 4. at night; 5. on Wednesday evening; 6. at 10 o'clock; 7. in 1821; 8. in the spring; 9. in the afternoon; 10. on Saturday morning; 11. on the weekend; 12. on Thursday; 13. on May 1st; 14. in the evening.