What is an object sentence?

The term "object sentence" is not a standard grammatical term. In traditional grammar, we talk about object nouns and object pronouns, which are the recipients of the action of a verb.

Object nouns are nouns that directly receive the action of a verb. For example:

* I ate the apple. (Apple is the object noun)

* The dog chased the ball. (Ball is the object noun)

Object pronouns are pronouns that function as objects. For example:

* He gave me a book. (Me is the object pronoun)

* I saw them at the park. (Them is the object pronoun)

It's possible that "object sentence" is a term used in a specific context or field, like linguistics or logic. If you can provide more context about where you encountered this term, I might be able to provide a more accurate explanation.