Tiangong Kaiwu's trip to parent-child activities - crystal trip - expansion activities children have a great time, Tiangong Kaiwu's crystal let us see it very shocking. I have always felt that the crystal is small in my heart. I have seen it today. I have learned that there are many types of crystals. Also let the children know a lot of crystal knowledge, see the horizon. Thank you teacher for organizing this meaningful activity.