3 sentences

1. 房子烧成了灰烬。

   fáng​zi shāo chéng le huī​jìn.

   The house burnt to ashes.

   Source: Tatoeba

2. 整座森林在大火中化为灰烬。

   zhěng zuò sēn​lín zài dà huǒ zhōng huà wéi huī​jìn.

   The entire forest was reduced to ashes in the fire.

   Source: Dong Chinese Dictionary

3. 火山口喷出了大量的灰烬和浓烟。

   huǒ​shān​kǒu pēn​chū le dà​liàng de huī​jìn hé nóng​yān.

   The crater spewed out a large amount of ash and thick smoke.

   Source: Dong Chinese Dictionary