"The writer sat in the armchair and started writing."
Translation:Писатель сел в кресло и начал писать.
Сесть, being perfective, is actually better translated as "to sit down," so there definitely is an implication of movement here which calls for accusative rather than prepositional :-)
Yes you would. That should be reported since simply saying "he sat in the armchair" implies he'd already been there for a while when we started talking about him.
Could написать be used here? If yes, what would be the difference in meaning? Having a hard time still with the perfective / imperfective thing.
Perfective verbs describe a single moment in time and have no duration, so you can't "start" doing a perfective verb's action. (nor can you resume it, prolong it, end it, etc)
The imperfective is used here because you're describing the actual process of writing, without a goal specified, and that's exactly what imperfective verbs are for. If the sentence was, say, "I sat in the armchair and wrote down my statement." then you would use perfective because the relevant bit of information is the statement having been written down: «Я сел в кресло и написал заявление.»
No. I'd say посидел is about process in the past, as "had been sitting for a while", meaning that now he is not sitting anymore.
So they still haven't fixed accepting feminine endings even though this was reported as early as 2016? come on Duolingo!
I used the feminine form of the verbs and duolingo marked it as a typo. I'm tired of duolingo oppressing women and apache attack helicopters with misogynist agenda. It's 2016 duo, please respect all 304 genders.