Which case is used when a noun or pronoun functions as a direct object, indirect object, or object of a preposition?

The appropriate case to use when a noun or pronoun functions as a direct object, indirect object, or object of a preposition is the objective case. In English grammar, the objective case indicates that the noun or pronoun is receiving the action of the verb or is the entity toward which the action is directed.

For example, in the sentence "She gave him the book," the pronoun "him" is the indirect object, and "the book" is the direct object. Both "him" and "the book" are in the objective case. Similarly, in "The teacher spoke to them," the pronoun "them" serves as the object of the preposition "to," which also places it in the objective case.

Using the objective case correctly helps clarify the relationships between different parts of a sentence, ensuring that it is understood who is doing the action and who is receiving it.