I think the sentence is ""Sống là một hành động." if it's "Living is an action.".
Makes sense. Cảm ơn So I guess "Living is acting" could also be acceptable...?
Yes and you don't really một to indicate that it's an action although it's better as it's more specific. For example: Cuộc sống chỉ là giấc mơ = Life is but a dream/Life is only a dream, yet một isn't required although you can use it.