2 sentences for 不简单 (bù​jiǎn​dān)

1. 这件事情背后的背景很不简单。

   zhè jiàn shì​qing bèi​hòu de bèi​jǐng hěn bù​jiǎn​dān.

   The background behind this matter is quite complex.

   Source: Dong Chinese Dictionary

2. 他年纪轻轻就能取得这样的成就，真不简单。

   tā nián​jì qīng​qīng jiù néng qǔ​dé zhè​yàng de chéng​jiù, zhēn bù​jiǎn​dān.

   It is quite impressive that he could achieve such success at such a young age.

   Source: Dong Chinese Dictionary