This study examines children's use of conjunctions.Three major issues are addressed: linguistic complexity, developmental differences, and ethnic differences.The subjects for the study--third, sixth, and ninth graders-were of Anglo, Black, or Hispanic ethnicity.They completed sentence fragments ending in the conjunctions and, but, because, and even though.These conjunctions can be paired, and-but and because-even though, where the second member of each pair is basically the negative of the first.The data indicate that the positive member of each pair was easier than the negative one; the complete order of difficulty for the four conjunctions was because < and < but < even though.The order of difficulty was constant across grades and ethnic groups.For all ethnic groups there was improvement in the use of conjunctions between third and ninth grade.However, the grade by which effective mastery of each conjunction was reached differed for the three ethnic groups, being in general earliest for Anglos and latest for Hispanics.