I've some difficulty in deciding whether to use the Simple Past or the Present Perfect.

One rule says that Simple Past is used to indicate that something happend at a specific time in the past.

Another rule says that the Present Perfect is used when there is some kind of connection between what happend in the past and the present time.

Which rule has to to be applied in the following example ?

Friends of Jane are waiting for her at the airport.
John:"She arrived (has arrived) at Kennedy Airport five minutes ago. I think we'll see her in half an hour."

Am I right that you must use the Simple Past when there is a definite time marker even though the past action influences the present time entirely.

Thank you in advance Emotion: smile
Yes I see what you mean with your question... I too would hesitate on this one.
However, I agree with you that the simple past is more appropriate here. With the verb 'to arrive' you put the emphasis on the action of finally reaching the airport, which happened at a definite point in time in the (recent) past. Now if you want to insist on the impact and the connection with a present situation, then I guess you could use a different verb, one that could express the time that has elapsed since the event that constitutes her arrival.
In which case maybe you could say 'She HAS BEEN at the Kennedy Airport for five minutes now' or 'It'S BEEN five minutes since she reached the airport' or something like that ?
With "ago", you have to use the past simple. "Just" is different, you can use both. But when there's a precise time marker, it's always the past simple.
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PieanneWith "ago", you have to use the past simple. "Just" is different, you can use both. But when there's a precise time marker, it's always the past simple.

Students in my French classes had trouble understading how the passé composé could be translated to English with both the simple past and the present perfect. I used your explanation of "precise time marker", and it seemed to help them understand their own language a little better. "I've just done something" is an entirely different construction in French, so it posed no problems.

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When I teach English tenses to French students, I always tell them to forget the French principle of "past", "present", or "future". The clues are quite different in English.

So, I ask them to see the things they want to express as if they were film-makers, and to cast a different light on the events. "What do you want to emphasize?" "What's the message you want to convey?" "Is it still going on at the moment you're speaking?" "How do you picture the next scene?" etc etc...

Do you teach English? Well, I guess you do...