i think to think ABOUT staying here should be ok too
I agree but DL (still) doesn’t accept it here. To my mind, “to think of” and “to think about” are interchangeable in English in most contexts, and certainly in the sentence here.
"Are you thinking about staying in this country?" should be an acceptable answer too.
Incorrect rendering: "Are you thinking of/considering staying in this country?" sounds more like it.
Not a native speaker, but "Do you think of staying in this country?" sounds quite awkward with the tense used.
Better to say " Are you thinking of staying ....?"
The above is an awkward translation that would rarely ever be used in English. "Do you intend/plan to stay in this country?" would be a better rendering in English
"Do you plan to stay in this country?" works.
Yes. When i start a sentence with "Do you think ..." I am probably going to disagree with what comes next. "Do you think a native speaker would say this?". No. I would say "Are you thinking of staying?"
I agree that using the construction with the ing form is the natural way. The correct sentence by Duolingo sounds unnatural.
why not ficando?
You should use infinitive after prepositions in Portuguese.