七个数复式三中三多少组怎么算

简介：No. 2 Middle School is a school on the top of the mountain. The road leading to the foot of the mountain is made of marble stone steps. There are forty-nine steps in total. If he carries a girl down the steps, the physical education teacher will be out of breath. However, after going down the steps, there is still a short distance to the school gate. A distance of tens of meters.