If John says "Ms JH has lived in Japan since 1987", shall I ask further where Ms JH is living now? Or shall I suppose that Ms JH still lives in Japan, so I don't need to ask?
there now vs. not here now
She has lived in Japan since 1987 means, (a) she still lives there now or (b) she no longer lives here now (i.e., in answer to an airport customs official's question, "How long has she lived in Japan?"--She's at the airport, leaving Japan for good, never to return again, "I've lived in Japan since 1987, but I no longer live here now."
Ex: John says: "Ms JH has lived in Japan since 1987."
Cas, according to your opinion, we use Present Perfect, we say specially the time Since, and yet we still cannot express the action whether finished or not; whether past or present? Is this the way we use Since, to express something we don't know about it now?
So we have to ask about JH at present, and John will tell you in Simple Present, getting rid of the time adverbial: "Yes, she still lives there now." Or "No, she no longer lives in Japan."
Is this what Since implying? John doesn't want you to know about her now, unless you ask him more?
But Cas said there are two meanings with Since:
How do you know which one meaning is implied in Since, if you don't ask?
If since was to have two meanings, then I suppose the sentence would have been followed with a 'but she now moved...'. This is when you have to ask... If it would have been 'since 1987 till 2000'. In this case, asking whether she moved or not sounds pretty obvious, but when 'since' is used stand alone, that would mean that she still is at her location.
Since would imply the finish unless stated otherwise. Now, just to play safe, it's better that you follow Casiopea's advice and ask. I don't think that anyone would notice english not being your mother language if you ask a question. They might only think that you're just a bit curious or you're trying to socialize. At least you won't be sayin 'Could you please help me to open that closed door?'
PS: - you're right about the 1987 to 2000. See, I got totally messed up while summarizing Rosencrantz and Guildenstern are dead. That book is not recommended for any person suffering from hysteria, demence, schizophrenia, melancholia or suicidal tendencies. It knocks you out with the 'freaky' explanations on the law of probability and more to go...