她的字迹很幼稚，很难读。

Her ___childish handwriting was hard to read.

我听到一个幼稚的声音对我说‘牵着我的手’。

I heard a ___childish voice saying to me "Take my hand."

他幼稚的行为惹恼了成年人。

His ___childish behavior annoyed the adults.