Look at is Plural as Well as Singular. Why do i have to use the "you All", which by the way nobody does?
You do not have to use the "You all" which is only heard in the southern states of the USA. It's Duolingo's mistake to require it. And DL is inconsistent on the issue, as many places they accept a simple "you" for meaning "you" (plural), whereas in other places, they don't. I expect it has to do with how many report it as a mistake. So we must bombard them with our reports.