It isn't. They just happen to be the fourth word in their respective sentences.
Mostly because of the telefon, I'd say. For instance, you svarar på email.
No, that sounds like he's talking to the phone itself. Possibly if he's talking to Siri… :)
svara i telefon is a set construction
I wrote, 'he finished answering the telephone', but this was marked incorrect, though I don't think it's different to 'he stopped answering the telephone'. Or?
I think the sentence is supposed to mean that he was old or lazy or ill and he stopped answering any calls for a period of time. "He finished answering the telephone" really means the end of just a single call.
'Finish' and 'stop' can often be used interchangeably in English, but in this case the meaning is different.
I really have to digest the structure here. In Seedish, there is no "the".
Yes. That is because this is an expression where Swedish prefers the indefinite, while English prefers definite.
Why wouldn't we write "Han slutade att svara i telefon" ? I thought the word "att" could be missed if preceded of "vill"
If he answered the phone this time, then finished answering, could you also use sluta? Or would something else be better?
You'd need to say something like han avslutade telefonsamtalet ('he finished the phone call') for that. Han slutade svara i telefon is understood to mean 'he quit answering the phone', not that he was done with answering one specific call.