Number + 点
The classifier 点 (diǎn) is used to express clock time in Chinese, equivalent to "o'clock" in English. It follows a number to indicate the hour. For example, 三点 means "three o'clock" and 零点 means "midnight."
我们约好明天早上九点见面。
Wǒmen yuē hǎo míngtiān zǎoshang jiǔ diǎn jiànmiàn.
We agreed to meet tomorrow morning at nine o'clock.
现在已经十一点了,该睡了吧。
Xiànzài yǐjīng shíyī diǎn le, gāi shuì le ba.
It's already eleven o'clock — time to sleep.
他每天六点半起床去跑步。
Tā měitiān liù diǎn bàn qǐchuáng qù pǎobù.
He gets up at six thirty every day to go running.