The crucial variable in good classroom teaching is the verbal behavior of the teacher. Through his questioning techniques--what questions he asks, how and when he asks them, how he replies to students, and how he stimulates students to reply to each other--the teacher can evoke a high level of class discussion and force students to go beyond the factual level of comprehension. To improve his questioning techniques, the teacher should (1) call on the less demonstrative students, unobtrusively correcting misinformation so that all in the class experience some degree of success, (2) sequence and pace questions carefully, (3) avoid using questions which deal with insignificant content or which require fact-recall, opinion, and "either-or" responses, (4) adapt questions to the particular subject areas under discussion, and (5) in teaching literature, use such questions as "Why?""Under what circumstances...?""How can you tell that...?""How would you compare...?""What are the probable causes or possible effects of...?" and "What would happen if...?" (JB)