3 sentences

1. 归根究底，人类是一体的，而这个小小的星球正是我们唯一的家园。

   guī​gēn​jiū​dǐ, rén​lèi shì yī​tǐ de, ér zhè​ge xiǎo​xiǎo de xīng​qiú zhèng​shì wǒ​men wéi​yī de jiā​yuán.

   Ultimately, humanity is one, and this small planet is our only home.

   Source: CCMatrix

2. 他的黑色外套与黑暗融为一体。

   tā de hēi​sè wài​tào yǔ hēi'àn róng​wéi​yī​tǐ.

   His black coat blended into the darkness.

   Source: Tatoeba

3. 中国就是一个自成一体的世界。

   zhōng​guó jiù​shì yī​ge zì​chéng​yī​tǐ de shì​jiè.

   China is a world of its own.

   Source: CCMatrix