In this paper, the authors study the relationship between the class of languages generated by grammars with production repetitions set and the class of adherence of languages, and prove that the class of adherence of contextfree languages is the proper subclass of contextfree languages and the class of adherence of regular languages is the proper subclass of regular languages. As a proper class of contextfree languagesthe class of linear languages, its adherence is the proper class of regular languages.