Translation:Tomorrow is the 18th.
English likes to have the definite article before dates, so whatever tense you use, write 'the 18th' rather than just '18th'.
Most commenters are using literal english translations for this simple phrase and expect it to be correct. Use natural english on how you would tell the date to someone, eg, Tomorrow is the 18th, or it's the 18th tomorrow (which coincidentally wasn't accepted and been reported).
who says, "it's the eighteenth day of the month tomorrow"? a bit awkward I think.
We do not say "Tomorrow is the 18th" in English. We say "It is the 18th tomorrow". Do you agree?
We do say Tomorrow is the 18th in American English. It is a very normal and common statement.
I guess "Tomorrow it is the 18th" should also be accepted as correct. What do you guys think?
Duo usually allows one typo provided that the typo does not make another actual word in the target language. However your word has two typos and that is probably why it is not accepted.
It can't be that bad since you have a 68-day streak and a ton of time invested in several languages.
Hey Lazy Einstein, is there any language left which you are not learning on duo?