Sixty tenth graders participated in this study of relationships between eye/voice span, phrase and clause boundaries, reading ability, and sentence structure. Results indicated that sentences apparently are "chunked" into surface constituents during processing. Better tenth grade readers had longer eye/voice spans than did poorer readers and exhibited more proficiency at chunking sentence structures into phrases and clauses. All subjects used essentially the same pattern of processing different types of sentences, indicating that ability level was not significant in the proficiency of dealing with right and left embeddings. (Author/AA)