Questioning is an essential process of learning and thinking. However, few students are willing to ask questions in class because of the pressure from many sources including their past experiences, teachers, peers, or themselves. A computer system NATA was designed in this research based on the two-phase questioning process to help students ask questions by reducing their questioning pressure. An experiment was conducted to study the effectiveness of NATA. More than 85% of the students in this research agreed that NATA made classroom questioning easier and more comfortable and could promote their questioning and the class? questioning atmosphere. The results also showed significant improvement of students? questioning behaviors after using the system.