批改作业时,常常发现有学生写出诸如“一棵大树高5厘米”“一张桌子长10厘米”“一根香肠长1米”等错误答案,令人啼笑皆非。仔细分析其中的原因,不得不对长度概念的教学过程进行回顾和反思。教学片断一:估测线段有多长教学中,我出示两条长度不同的线段,让学生采用直尺来测量:“这两条线段的长度各有几厘米?”学生经过测量后 When correcting homework, it is often ironic that students write wrong answers such as “a big tree 5 cm tall”, a table 10 cm long, and a long 1 meter long sausage. Carefully analyze the reasons, have to review the length of the concept of teaching process and reflection. Teaching a fragment one: to assess how long the line segment Teaching, I showed two different lengths of lines, so that students use rulers to measure: “The length of the two lines each have a few centimeters? ” After students measured