电脑开机要等一会儿。

Diànnǎo kāijī yào děng yíhuìr.

You need to wait a bit for the computer to start up.

手机开机以后给我打电话。

Shǒujī kāijī yǐhòu gěi wǒ dǎ diànhuà.

Call me after you turn on your phone.

每天早上八点自动开机。

Měitiān zǎoshang bā diǎn zìdòng kāijī.

It turns on automatically at eight every morning.