What are the modifiers used to modify S, V, IO and  DO? 

        a. The subject in a sentence is always a noun,  a noun phrase

            or a noun clause.

          In English, adjectives, adjective phrases and adjective clauses

          are used to modify the subjects.

     b. The verb in a sentence can be a single verb or a verb phrase.

         They will be modified by adverbs, adverb phrases and adverb

         clauses.

    c. The direct object and indirect object in a sentence are nouns.

       Therefore, they are modified by adjectives, adjective phrases and

       adjective clauses.