"Eating in the library is forbidden."
Translation:Το να τρως στη βιβλιοθήκη απαγορεύεται.
"Απαγορεύεται να τρώς στη βιβλιοθήκη." is one of the accepted translations so I don't know why you say it was marked wrong because you didn't use "το". Did you report it? You most likely had another error.
It's always best to report sentences that are not accepted. That way you may learn what mistake you made but also we can see what we need to edit.
"Το να τρως στη βιβλιοθήκη απαγορεύεται."
"Απαγορεύεται να τρως στη βιβλιοθήκη."
are correct it seems it should also be correct to say
"Απαγορεύεται το να τρως στην βιβλιοθήκη.",
but this was marked wrong. Can someone enlighten me?
I remember reading it was optional to drop the "ν" off "στην" in cases like this. In many instances duo marks it wrong to leave on the "ν". Can I gather from this that native Greek speakers would consider it strange to hear the "ν" in such cases. Thank you.