2 sentences

1. 沟通是整个项目中不可或缺的一个环节。

   gōu​tōng shì zhěng gè xiàng​mù zhōng bù​kě​huò​quē de yī gè huán​jié.

   Communication is an essential link in the entire project.

   Source: Dong Chinese Dictionary

2. 智能手机已经成了现代人生活中不可或缺的工具。

   zhì​néng shǒu​jī yǐ​jīng chéng le xiàn​dài​rén shēng​huó zhōng bù​kě​huò​quē de gōng​jù.

   Smartphones have become an indispensable tool in modern life.

   Source: Dong Chinese Dictionary