[susan53]

Thank you roozbehrah. I hope you find the answers useful. If you've got any of your own, don't hesitate to post them.

[terryfrd]

Great answer. Very thorough. Good to see a discussion of tense and aspect. I would just add a couple of things. First with the present perfect there always a sense of current relevance. The speaker/writer perceives that an event/action done or begun in the past is relevant to the present. "I've eaten lunch" (I'm not hungry any more). "Over the last five weeks, Joe has earned $5000". (So he's feeling pretty happy, etc., etc.) Secondly, with the progressive, there is also the sense that the situation is somehow temporary. "I'm living in Bangkok" is not the same as "I live in Bangkok." To me, "Over the last five weeks, Joe has been earning $5000" seems a bit strange. A more realistic sentence would be something like, "Over the past five weeks, Joe has been averaging over 1200 dollars a week." That situation may or might not continue, but it is not finished,