"Due to lack of water we could not cook."
Translation:Pro manko de akvo, ni ne povis kuiri.
"povis" is simple past, only "kuiri" is in the infinitive.
As in English - "could" in simple past, "cook" in infinitive.
Please don't. It's nearly impossible to tell silly questions from real questions from confused learners.
English was not my first language either, what I meant was, I was being stupid, and careless, not trying to make a joke.
I was tempted to call it "Poe's law" (see e.g. here, here, or here) -- though it's not quite the same (this is not fundamentalism, creationism, or extremism), I think it's still in the same general category of "mistaking genuine ignorance for a parody of ignorance".
(Conservapedia, which can be fun reading for a laugh, has a more general formulation including the word "stupidity" but I think even that is a bit strong for what people here display - I think it's more beginner-ism or ignorance or a lack of step-by-step grammar instruction than stupidity per se.)