soften

她放了一些音乐来缓和紧张的气氛。

She played some music to ___soften the tense atmosphere.

把香蕉放在微波炉里加热几秒钟可以软化它。

Microwaving the banana for a few seconds will ___soften it.

老师放慢语速来缓和批评的语气。

The teacher slowed her speech to ___soften the tone of her criticism.