"I am very thirsty now."
So, duo ignores the fact that 很，真，非常, etc are all gradual intensifiers but insists they ALL mean very. I.e I learned that 非常 is similar to extremely in English, but duo always counts that wrong. But, somehow they expect us to magically differentiate between all of them?
I'm not 100% sure because I'm still a loser at Chinese, but 我非常渴了 (or 很 or any other verb) do not sound right to me, or is at least uncommon. Remove the verb and 了 becomes mandatory: 我渴了。我饿了。