Girls as young as 4 or 5 have no trouble finding  the raw materials for schemata.其中as young as 4 or 5是什么用法？

【答】Girls as young as 4 or 5 等于：Girls who are as young as 4 or 5 

Kids ages 9 through 12 should get more information about puberty.其中ages 9 through 12是什么用法？我只见过aged 9 to12。

【答】Kids ages 9 through 12 等于：Kids of ages 9 through 12 

As we know, the children of various kinds of ages enjoy listening to the stories. 大家知道，各种年龄的学生都爱听故事。

Children of all ages should be outdoors several hours a day. 

各个年龄段的孩子每天都应户外活动几个小时。

These criteria are demanding in and of themselves.其中demand in 是什么搭配，在词典里没有查到…

【答】demanding 在这里是形容词，意为“adj. 苛求的；要求高的；吃力的”。These criteria are demanding 这是主系表结构，不是进行时。in and of itself：固定词组，指“事物自身”（复数时用in and of themselves）。就是说：这些标准自身要求很高。

The gender differences in the prevalence of eating disordering are among the largest reported for mental disorders. 其中among the largest reported，reported是名词吗？

【答】reported 是过去分词作定语，修饰the largest (最高级之后经常省略已知的名词：differences) ，意为“据报道的；据报告的”。reported 修饰the largest differences（最大的差别）