在中学物理教学中发现有好多经过原始公式推导出来的公式、结论,常常把它们称为“二级结论”.这些二级结论的确为解答这类问题中许多题目带来了很大的方便,在平时的教学中发现,使用久了之后,导致忘了判断或者就不进行判断,直接使用这些二级结论导致出错的情况.文中列举几例来说明. In physics teaching at middle school, there are many formulas derived from the original formulas, and the conclusions are often referred to as “secondary conclusions ”. These second-order conclusions do bring a great deal of answers to many of these problems Convenient, found in the usual teaching, after a long time use, leading to forget the judge or not to judge, the direct use of these two conclusions lead to errors .There are several examples to illustrate.