With a large class and a third-grade baby to brush, each project is basically about 30 minutes, half a day can not brush too much, to make up time to play the project, I feel that adults are very tired of counting the time to queue. The big interest in most projects is not very high. The little baby is very happy to experience the snack teacher, the little nurse and the like. The firefighter is too hot and the queue will start for 1 hour. The knowledge-based doctors, banks, food quality control will attract older children.