小单小双是什么数字

简介：This was naturally a small episode in the class. It was innocuous. Tong Liancheng started the class. He directly marked the knowledge points on the blackboard without using books and wrote them out one by one in a clear and logical manner. It has to be said that Tong Liancheng The teacher's skills as a ten-year-old teacher are still good, and his knowledge level is profound.