This study assessed the effectiveness of five hours of distributed training on three-year-old children's comprehension and production of the passive, negative, possessive and negative passive syntactic structures. A comprehension test identified 20 children who did not evidence understanding of these structures. Subject were randomly assigned to experimental and control groups. Experimental subjects received daily training. Toys in different arrangements served as exemplars of the structures. A readministration of the comprehension test to all children after three weeks showed significant improvement among experimental subjects, who also performed well on a test for production of these structures. These results were offered as evidence of the influence exerted by certain environmental conditions on basic language ability. [See ED 050 120 for a summary of this study.] (Author/CK)