八 (bā) is the number 'eight' in Chinese. It is considered a lucky number in Chinese culture because its pronunciation is similar to 发 (fā), meaning 'to prosper.' It is used in counting, dates, quantities, and numerous everyday expressions.
他们一家八口人住在一起。
Tāmen yī jiā bā kǒu rén zhù zài yīqǐ.
Their family of eight all live together.
我每天早上八点出门上班。
Wǒ měitiān zǎoshang bā diǎn chūmén shàngbān.
I leave for work at eight o'clock every morning.
这个项目已经进行了八个月了。
Zhège xiàngmù yǐjīng jìnxíng le bā gè yuè le.
This project has been going on for eight months already.