This study attempted to explore the possibility of increasing sensitivity to syntactic structure by exposing subjects representing a range of ability to a programed sentence structure module. Students in three ninth grade classes who had completed four weeks of supplementary work with "English Sentence Structure: Programed Exercises" and scored 70 percent or higher on achievement tests were tested using the "Perception of Alternate Structures Test" to determine if they would score higher than a comparable group of tenth graders who had not had instruction in the sentence structure module. Although the mean score on the structure test for the tenth graders was not higher than the ninth grade posttest mean, it was significantly higher than the ninth grade pretest mean. Thus, the results of this project affirm that sensitivity to syntactic structure can be increased by direct instruction, although the extent to which such increased sensitivity to structure can lead to improvement in reading comprehension skills is yet to be adequately demonstrated. (A background of related studies, descriptions of materials and procedures, and a brief bibliography are provided.) (See related documents CS 200 569, and CS 200 570.) (MF)