Here's why:
* Subject pronouns perform the action in a sentence. They are used as the subject of a verb. Examples include "I," "you," "he," "she," "it," "we," and "they."
* Object pronouns receive the action of the verb. They are used as the object of a verb or a preposition. Examples include "me," "you," "him," "her," "it," "us," and "them."
For example:
* Subject pronoun: We went to the park. ("We" is the subject of the verb "went")
* Object pronoun: The dog chased us. ("Us" is the object of the verb "chased")