Neither. The right preposition here is "about". There is nothing bad about (doing st.). Example: "There is nothing bad about asking a question here." The other two words don't fit this sentence.
3 dicembre 2014
2
1
1
'In' is possible, but 'about' is more natural.
Definitely not 'at'.
3 dicembre 2014
0
1
Non hai ancora trovato le tue risposte?
Scrivi le tue domande e lascia che i madrelingua ti aiutino!