大多数两岁的孩子还没有分享这个概念。

The ___notion of sharing is unknown to most two-year-olds.

他对艺术应该是什么的传统观念提出了挑战。

He challenged the traditional ___notion of what art should be.

一想到自己可能是错的，他就感到不安。

The very ___notion that he might be wrong was unsettling to him.