"She never answered."
Translation:Ela nunca respondeu.
To me, it feels as though, in English at least, to say "she never had answered" is missing more context, something on the end to close the sentence or add to the story ... "she never had answered, so I stopped asking." It feels more like this would be specific to a time period or event or specific context. Where as "she never answered" feels more open to any time in the passed, sem context. "Irrespective of space or time, she never answered." That is just my take on it.
While it is not listed in the list of hints, I feel as though "ligou" would work in place of "respondeu." Would a Brazilian say "ela nunca ligou" to say that to mean "she never answered the phone?" Or, I might be misremembering, but "liga and desliga" can mean "pick up and hang up," right?