3 sentences for 投机 (tóu​jī — congenial)

1. 两人聊得投机，不知时间已过半夜。

   liǎng rén liáo de tóu​jī, bù​zhī shí​jiān yǐ guò bàn​yè.

   The two were having such a good conversation that they didn't realize it was already past midnight.

   Source: Dong Chinese Dictionary

2. 由于性格相似，他们两人谈得很投机。

   yóu​yú xìng​gé xiāng​sì, tā​men liǎng rén tán de hěn tóu​jī.

   Because of their similar personalities, the two of them hit it off well.

   Source: Dong Chinese Dictionary

3. 老友重逢，大家聊得十分投机，他感到心情甚畅。

   lǎo​yǒu chóng​féng, dà​jiā liáo de shí​fēn tóu​jī, tā gǎn​dào xīn​qíng shèn chàng.

   Reunited with old friends, everyone chatted very congenially, and he felt very happy and relaxed.

   Source: Dong Chinese Dictionary