2 sentences for 質 (zhì — plain)

1. 他的作品风骨嶙峋，质而不华。

   tā de zuò​pǐn fēng​gǔ lín​xún, zhì ér bù huá.

   His works are forceful and lofty, simple but not ornate.

   Source: Dong Chinese Dictionary

2. 这种质朴的乡村生活让他感到非常放松。

   zhè zhǒng zhì pǔ de xiāng​cūn shēng​huó ràng tā gǎn​dào fēi​cháng fàng​sōng.

   This simple and rustic country life makes him feel very relaxed.

   Source: Dong Chinese Dictionary