Patterns and possibilities of free modifiers in written composition were studied. One purpose of the investigation was to help students communicate more effectively in writing. A more specific purpose was to determine if complicated syntactic elements used as free modifiers could be lifted from the complex subject of grammar and be presented as "sentence additions." This study thus involved instruction and practice in writing, and traced for five weeks the development of free modifiers in the writing habits of three tenth grade students. For 20 lessons, subjects were asked to put complex structures into use as "additions" to kernel sentences--"clusters" suggested to them through the use of self-supplied models and signal words. The subjects practiced naturalistic language tasks and shared experiences in writing, and without reference to grammar. As a result, not only the use of different kinds of free modifiers increased but also the average number of words per communication unit. It is concluded that growth in written expression can be based on free modifiers and on the student's operational use of clauses, phrases, and sentence structure. (Author/DB)