This paper discusses two influential studies on relative clauses (RC), and addresses the development of relative clauses in the interlanguage of advanced Chinese English-as-a-Second-Language speakers in light of the theory of Accessibility Hierarchy (AH). As the two theories predict, avoidance of RCs is typically found with oblique and genitive rather than with objects or subjects of RCs. Error types are similar to those found for learners of other first-language backgrounds. The use of Resumptive Pronouns in Genitive RCs, at the bottom of the hierarchy, is of particular interest. To explain these findings, a processing motivation, hypothesized to underlie the AH and its reflexes in interlanguage, is outlined. (Author/JL)