Lots of 6-year olds, 9-year olds, 12 year-olds, a couple teenagers, and I do have 2 adult students.

很多六岁、九岁、十二岁的学生，几个青少年，我也有两个成人学生。

和钢琴老师 - SpeakingMax英语口语达人

I did have a friend who was beat up by about twelve or thirteen kids who were all between ten and eleven years old,

我有个朋友曾被十二三个孩子殴打，都在十岁和十一岁之间。

大城市是否危险？ - SpeakingMax英语口语达人

So I came to Canada when I was twelve,

那么，十二岁的时候，我去了加拿大，

第二外语，英语 - SpeakingMax英语口语达人