What is the only word that not in predicate of following sentence Nathan threw his grammar book at wall?

The word "at" is the only word that is not in the predicate of the sentence "Nathan threw his grammar book at the wall."

Here's why:

* Predicate: The predicate of a sentence tells us what the subject does or is. It includes the verb and any objects or complements that modify the verb.

* Subject: The subject of the sentence is "Nathan."

* Verb: The verb is "threw."

* Objects: The objects are "his grammar book" (direct object) and "the wall" (prepositional object).

The word "at" is part of the prepositional phrase "at the wall," which modifies the verb "threw" but is not the direct object of the verb.