Basic examples of time prepositions include: at, on, in, before and after. They are used to help indicate when something happened, happens or will happen. It can get a little confusing though, as many different prepositions can be used. For example:
1. I was born on July 4th, 1982.
2. I was born in 1982.
3. I was born at exactly 2 am.
4. I was born two minutes before my twin brother.
5. I was born after the Great War ended.