她生气时的撅嘴行为显示出一种幼稚的孩子气。

Her pouting when upset shows a certain ___childishness.

他总是为琐事抱怨，这显示出他的幼稚。

His constant complaining over trivial matters shows his ___childishness.

她笑声中的那种天真烂漫总能让人心情愉悦。

The ___childishness in her laugh always brings joy to those around her.