Here's why:
* Direct objects receive the action of the verb.
* Objective case pronouns are used when the pronoun is the object of a verb or preposition.
Examples:
* Correct: "The teacher praised him for his hard work." (Him is the direct object of the verb "praised")
* Incorrect: "The teacher praised he for his hard work." (He is in the nominative case, not the objective case)
Common objective case pronouns:
* me
* you
* him
* her
* it
* us
* them