The purpose of this investigation was to study the effect that four alternate types of instruction had on the frequency with which high inquiry questions were asked by preservice secondary science teachers. High inquiry questions involve comparing, explaining, conditional inferring, and evaluating. The four alternative instructional treatments were: placebo, classification, planning, and both classification and planning. For the study, 62 subjects taught a peer microteaching lesson prior to (pretest) and immediately following (posttest I) instruction on questioning. Forty-six of the subjects who continued into student teaching the next semester then taped one of their typical lessons (posttest II). The frequency with which subjects used the question categories during the lessons was compared with pretest data, using analysis of variance and covariance. Among results, data revealed that all treatment groups increased their frequency of high inquiry questions. (Author/CP)