化简比

问题情境

在综合实践课上，老师让同学们“以三角形的旋转”为主题进行数学活动，如图（1），在三角形纸片ABC中，AB=AC，∠B=∠C=α．

操作发现

完型填空。

    My name 1Tim. I'm 16 years old. I'm a junior high school student. Tomorrow is the weekend. We have no classes. My parents2 going to work, but we are going to be very busy tomorrow. My mother is going to buy a sweater 3my grandmother. My father is going to visit my aunt and uncle. I'm going to4computer games with my cousin. Tomorrow evening we are going to have 5big dinner. After dinner we are going to the cinema to see a film by car. I think we are going to have a nice weekend.