Formal:
* 回來 (huí lái) - This is the most common and general way to say "come back" or "be back."
* 返回 (fǎn huí) - This means "return" and can be used in more formal settings.
Informal:
* 回來 (huí lái) - This is also used in informal settings.
* 回來啦 (huí lái la) - This adds a particle "la" to the end, making it more casual.
With a specific time:
* 過會兒回來 (guò huìr huí lái) - This means "be back in a while."
* [时间] 後回來 (shí jiān) hòu huí lái) - This means "be back after [time]." For example, "五分钟後回來 (wǔ fēn zhōng hòu huí lái)" means "be back after five minutes."
Example sentences:
* 我過會兒回來。(Wǒ guò huìr huí lái.) - I'll be back in a while.
* 我下午兩點回來。(Wǒ xiàwǔ liǎng diǎn huí lái.) - I'll be back at 2 p.m.
* 我明天返回。(Wǒ míngtiān fǎn huí.) - I'll return tomorrow.
Remember to choose the appropriate phrase based on the context and formality of the situation.