2 sentences

1. 市面上有很多劣质商品。

   shì​miàn shàng yǒu hěn​duō liè​zhì shāng​pǐn.

   There are many low-quality products on the market.

   Source: Dong Chinese Dictionary

2. 这种劣质材料经不起高温。

   zhè zhǒng liè​zhì cái​liào jīng​bu​qǐ gāo​wēn.

   This inferior material cannot withstand high temperatures.

   Source: Dong Chinese Dictionary