一次教一年级小朋友学习《比一比》,其中有一环节是要求学生“两手分别握乒乓球和棉花球。”感受“形体相仿,但质地不同、软硬不同”。备课时,为了使形体更相仿,我将棉花球换成学生更容易自备的面团,没想到…… Once taught first grade children to learn “one ratio”, one of the links is to require students to “hold hands with table tennis and cotton ball with two hands.” Feel “similar body shape, but different texture, different hardware and software.” During the lesson preparation, in order to make the figure more similar, I replaced the cotton ball with the dough that the students prepared more easily, I did not expect ......