A student was asking me, when and why should we choose the present perfect as opposed to the past simple when what has happened is in fact in the past? The sentence that we were reading narrated about a woman, and it was telling us that in the last 10 years she has lived in four different places, but then immediately after this it said, "At the moment she is in a different country (not one of these four) running a restaurant..." I wasn't sure how to explain to him the reason why or even how they could use the present perfect in this case. I merely told him perhaps she has gone to another country within the last few months of those 10 years which would make it correct to use the present perfect followed by the present continuous. Can you give me a better explanation to use? Also don't forget that they want to know why wouldn't the past simple be sufficient to use in this case?
