Abstract: There are two instructional modes when computer is applied to education, Tool mode and Tutormode. This paper reviewed issues of theoretical and empirical researches on these two fields, andproposed a cooperative tool mode with Windows PBrush. A one-week instruction in geometric reasoningwas conducted and its effect on geometric knowledge and reasoning ability was investigated by pre-posttest experiment. Attitude and motivation of students and teachers were investigated with surveys andinterviews. it also analyzed learning process of students with work analysis method. The result showedthat:Cooperative tool mode instruction brought on significant outcomes in reasoning ability, geometricknowledge, and study motivation than cooperative CAI; proper instructional methods can promoteinstruction effects, feature and quantity of information representation can affect the learner's cognitiveconstruction.

Key words: Tool mode, CAI, instructional effects, representation, Cooperative learning