牛奶在温暖的环境中会发酵变酸。

Milk will ___ferment and turn sour in a warm environment.

虚假新闻常常煽动社会不安。

Fake news often ___foments social unrest.

社交媒体上的讨论引发了公众情绪的激烈发酵。

The discussions on social media caused a ___ferment of public emotions.