"The teacher eats from twelve to one."

Translation: 老师从十二点到一点吃饭。

[jackskels]

The use of cong(从) and dao(到), is the "formula" you employ express from one time to another in mandarin.

从 + Time 1 + 到 + Time 2.

Hopefully this explanation is helpful to someone.

[uncannyrain]

Is it wrong to say 从十二点到一点老师吃饭? If it is, why? Any specific rule?

[Cs1987]

It is correct, and it is accepted now.

[KlaraWeise]

Is there a way to know if its one in the afternoon like 1pm or 13:00?

[n3uromante]

wrote 老师吃饭从十二点到一点, is it wrong? Should 吃饭 only come at the end?

[Cs1987]

That is incorrect word order. The time has to come before the verb in Chinese.

[n3uromante]

Thanks man.

[maartendoc]

从 (cóng) = from/to follow
到 (dào) = to (a place)/until (a time)/to arrive