formative

大学时期是他性格形成的阶段。

The college years were a ___formative stage in his personality development.

她的大学经历对她的性格发展起到了塑造作用。

Her college years were ___formative in shaping her personality.

在英语中，后缀 '-ly' 是一个构词成分，可以将形容词转化为副词。

In English, the suffix '-ly' is a ___formative element that turns adjectives into adverbs.