@alecCowan: "pienses" was just a typing mistake. I wanted to write "piensas", of course! The thing with the imperative I already knew (glad I at least got that one right...).
And thanks for your further explanations
I feel better now, your idea of actions happening/not happening is evident. I will keep that in mind.
@ BenCondor: you are totally SO right. I'm often confused because I can't, sort of, let go the English language patterns and implications. Not helpful. And, no, it does NOT square with the way of teaching of my professors
not at all.