培养推理能力是平几教学的重要任务。平几第二册课本在证题中正式引入推出符号“(?)”,使得书写形式简洁,层次清楚。但是部分学生会感到不易掌握,出现运用不当的现象。因此对“推出”符号的使用必须加强训练,以促进推理能力的培养。我们在教学中采取以下步骤进行分层次的练习。 Training inference ability is an important task of teaching a few. The second volume of the textbook is officially introduced in the title of the introduction of the symbol “(?)”, Making writing simple, clear level. However, some students find it hard to grasp the phenomenon of improper use. Therefore, it is necessary to strengthen training on the use of the “introduction” symbol so as to promote the cultivation of reasoning ability. We take the following steps in teaching to practice at different levels.