3 sentences

1. 这种清洁剂能轻松去除顽固污渍。

   zhè zhǒng qīng​jié​jì néng qīng​sōng qù​chú wán​gù wū​zì.

   This cleaner can easily remove stubborn stains.

   Source: Dong Chinese Dictionary

2. 他的思想非常顽固，很难接受新事物。

   tā de sī​xiǎng fēi​cháng wán​gù, hěn nán jiē​shòu xīn shì​wù.

   He is very stubborn and finds it hard to accept new things.

   Source: Dong Chinese Dictionary

3. 这种洗涤剂能有效洗涤各种顽固污渍。

   zhè zhǒng xǐ​dí​jì néng yǒu​xiào xǐ​dí gè zhǒng wán​gù wū​zì.

   This detergent effectively removes all kinds of stubborn stains.

   Source: Dong Chinese Dictionary