"None of us are perfect."
Translation:Nenhum de nós é perfeito.
I'm not sure about Portuguese (I'm still at the toddler stage in that language), but the English sentence can be either plural or singular. Although not as common you'll find "None of us is perfect" is perfectly good English. A crude Google test: singular 900,000 hits, plural 1,770,000 hits.
I used Google too before adding my original comment. See for instance http://www.grammarmudge.cityslide.com/articles/article/1026513/9903.htm. This article seems to take the view that "us" is plural so the verb should be plural.
It is interesting that learning Portuguese teaches me something about my own language too.
I agree, that's been my experience too. About this sentence I feel more comfortable with "None of us are perfect" but, as you can see, my simple Google test shows many people use the singular. The Oxford dictionary has this to say:
It is sometimes held that none can only take a singular verb, never a plural verb: none of them is coming tonight rather than none of them are coming tonight. There is little justification, historical or grammatical, for this view. None is descended from Old English nān meaning ‘not one’ and has been used for around a thousand years with both a singular and a plural verb, depending on the context and the emphasis needed.
So they seem to imply that the singular is the default and it's people like me who need reassurance that I'm not wrong. The dictionary doesn't seem to agree with the argument in your link because in their examples "them" is plural and they still permit "is".