I made this simple little foldable so the younger boys could refer to it as needed.
I took a large sheet of paper and folded it into thirds, then I cut the top and bottom thirds in half to make two flaps. I folded it up and labeled the top sections, subject and predicate.
Under the subject flap, I labeled the two sections, Nouns and Pronouns and Adjectives, the parts of the subject.
Under the noun flap, I gave explanations for the types of nouns and guidelines for plurals and singular nouns. Under the adjective flap, I gave a little description of adjectives and some guidelines.
Under the predicate flap is a definition of the predicate are the two flaps for the parts of a predicate, Verbs and Adverbs.
Under the verb flap is a definition of types of verbs and a rule about singular and plural verbs. Under the adverb flap is the definition of adverbs.