[daenglishteacher2007]

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?

[STCrowley]

Hey, my advice is this: you can use the past simple almost always. At least, in American English. . . I teach a lot of Germans, and they want to use the present perfect way too often.

But, why do we use it? I tell my students that it has an extra 'feeling' of currentness (it is, after all, a present form) which means that it's the status SO FAR. For example, in the last ten years, I've lived in the U.S. and Germany. . . but the formulation means that I'm certainly not ruling out a move to Italy. (I hear they have better winters.) Or, if I say 'I've had a bad couple of days,' then I'm expressing that I'm still having problems but 'I had a bad couple of days' indicates that I think I've put it behind me and I'm moving on.

Does that make any sense?

[kisito]

This question recurs everywhere. The perfect tenses (present perfect, past perfect, present perfect progressive, future perfect) are more recurrent in British English. It is not the easiest thing to explain. Through repeated practice students will know the difference.
But we use the past simple when an action ended in the past and we use the present perfect when an action started in the past but may still have relevance to the present. By the way there are over 7 reasons why we use the present perfect. In the sentence above "She has lived in different places in the last ten years." This sentence is relevant to the present in that this habit of living in different places has not ended. She is currently living in a new place after moving in from some other place. Sometimes the present perfect suggests that the action may still go on in the future - enter present perfect continuous.
But let's stick to the present perfect vs. Past simple.
We also use the present perfect in similar sentences using FOR or SINCE. For example : I have lived abroad for 10 years.
I have lived in London since 2000.
I have always wondered why it is called PRESENT PERFECT when it talks about the past. The reason is that an understanding of the past action can perfectly define the action of the present. There is a present perfect vs. Past simple board game on this page to practice the differences.
Check out this interactive wheel game to practice present perfect vs. past simple
More tenses vs. tenses games can be found here

[daenglishteacher2007]

Thank you, you have been very helpful.