Here are some examples:
* "I gave the book to *him*." Here, "him" is the object of the preposition "to".
* "She walked *with* *me*." "me" is the object of the preposition "with".
* "The dog ran *around* *us*." "us" is the object of the preposition "around".
Remember: The object of a preposition is the noun or pronoun that follows the preposition and receives its action.