I finally started with children under ten years old.
(First parentheses: I held it in for a long time before I came up with this sentence... I am afraid of being aggrieved... You have to be considerate of me! I am a copywriter!)
(Parentheses again: This is an article I wrote last year. Because the quality was poor at that time, I still haven't finished filling it out... The Olympics are coming and I can't be decadent anymore... I will finish it this summer vacation)