2 sentences

1. 他迅速由悲伤转为愤怒。

   tā xùn​sù yóu bēi​shāng zhuǎn​wéi fèn​nù.

   He quickly turned from sadness to anger.

   Source: Dong Chinese Dictionary

2. 听到教官的口令后，操场上的士兵们迅速由立正转为稍息。

   tīng​dào jiào​guān de kǒu​lìng hòu, cāo​chǎng shàng de shì​bīng men xùn​sù yóu lì​zhèng zhuǎn​wéi shào​xī.

   Upon hearing the drill instructor's command, the soldiers on the field quickly shifted from attention to at ease.

   Source: Dong Chinese Dictionary