教师要用好题来锻炼学生的思维,教师更要编好题,锻炼自己,教育别人。在七年级数学新编教材中一道裁长方形的例题就给了我们一些重要启示,并且能够引申得出结论:“在一个面积为S的正方形中,一定能够裁出一块面积小于或者等于S/2的长方形。当这个长方形的面积大于S/2时,在原正方形中一定裁不出来”。 Teachers should use good questions to train students’ thinking. Teachers should make good questions, exercise themselves and educate others. The example of a squared rectangle in the seventh grade mathematics textbook gives us some important revelations and can lead to the conclusion that: “In a square with an area of ​​S, one must be able to lay out an area of ​​less than or equal to S / 2 rectangular when the rectangular area is greater than S / 2, the original square must not be cut out ”.