There are a number of preposition words that change the meaning of a phrase when used with a particular word. For example, you can use Occupied with different prepositions, and you will get a different meaning every time. You can see the examples below:
1. Occupied in
Occupied in (doing a job)
Example:He is fully occupied in writing a book.
2. Occupied by
Occupied by (thing)
Example: That house is occupied by a marriage party.