3 sentences

1. 这个问题涉及极大的复杂性。

   zhè gè wèn​tí shè​jí jí dà de fù​zá​xìng.

   This issue involves great complexity.

   Source: Dong Chinese Dictionary

2. 这部电影的主题是关于人性的复杂性。

   zhè bù diàn​yǐng de zhǔ​tí shì guān​yú rén​xìng de fù​zá​xìng.

   The theme of this movie is the complexity of human nature.

   Source: Dong Chinese Dictionary

3. 那个书呆子根本不了解现实社会的复杂性。

   nà gè shū​dāi​zi gēn​běn bù liǎo​jiě xiàn​shí shè​huì de fù​zá​xìng.

   That nerd doesn't understand the complexity of real society at all.

   Source: Dong Chinese Dictionary