她幼稚的笔迹让人难以阅读。

Her ___childish handwriting made it difficult to read.

我听到一个幼稚的声音从操场上喊叫。

I heard a ___childish voice shouting from the playground.

他幼稚的行为惹恼了其他成年人。

His ___childish behaviour irritated the other adults.