He is working - tells us that he is at work right now. It makes no reference to the past. It only speaks of the present time. He has been working - tells us that his work is ongoing from some point in the past. He had been working - tells us only about the past. It makes no reference to what he is doing at the present time.
It means that that person was working the other one means they are working right now
Sasquatch has been sighted
Sasquatch has been sighted
"He is working" implies that "he" is working right now, so far as you know. "He has been working" does imply that "he" was working, perhaps for a while, but it doesn't say specifically that "he" is still working right now.
The difference is that working hypothesis is that your still working on it but the hypothesis that your not working on it.
the difference is simple had been working is past tense so i had been working but i broke my leg that means you do not work any more have been working means you are working just not rite now hope this helps
difference between temporary and permanent working capital needs
what is the difference between the memory store model and the working memory model?
Much the same as the difference between to and in.
Gross working capital is the amount company invested in current assets while net working capital is the difference between current assets and current liabilities.
a working mother has more responsibilities
one has been on the end