As we know the TENSES of English can be rather confusing for learners this is why I have decided to come up with a spectacular example using a made-up context which ought to help us see how the tenses involved work.
Imagine a situation. A person had worked at the office for 6 years and, say, on the 3 of March 2006 at 10 AM he was officially dismissed. But he was given one extra hour (until 11 AM) to collect his articles and say goodbye to his colleges. On the same day at 10.05 AM a new worker came to take his post over and he asked about the time having been spent by the old worker here. What tenses would fit for this situation? Let me give you my versions.
I think that the following TENSES are possible: (Do you agree?)
New Worker asks at 10.05 AM:
a) How long did you work here?
B) How long were you working here?
C) How long had you been working here until today?
D) How long had you worked here until today?
Is there any significant difference in subtleties between those four?
I also wonder whether it would be OK to use the Present Perfect in such a situation.
E) How long have you worked here?
I don’t feel comfortable with it, though. What do you think?
As for the answer of the old worker. I think that the TENSES used in the questions are OK. However, I am considering other options which I am not sure about.
F) I have been working here for the last 6 years. (Would it be correct to say it at 10.05 AM or is it only OK to say before 10.00 AM? Remember that he was dismissed at 10.00)
G) I was working here for the last 6 years. (I think it’s wrong. Do you agree?)
Best Answer
A. Working took place in the past. (A period of time is implied, of course, since you had to work for a period of time, but that fact isn't specified in this tense usage.)
B. Similar to A, but working took place over an unspecified period of time in the past.
C. Working took place over a period of time in the past. The tense specifies that there is a time also in the past that the period ended. (In your sentence, "until" is the wrong preposition; "before" is correct. Also, "before today" must imply "before your termination today"--which it does--to be correct.)
D. Working took place over an unspecified period of time in the past. My answer to C also applies here.
E. The person is still working here, and you want to know when he started. This isn't consistent with your scenario, so presumably that's why you don't feel comfortable with it. :)
F. It would be correct if the person isn't yet seeing his employment as being in the past. ("I have been working here for six years, and I'll be darned if I give up my job without a fight." would be an obviously correct usage, for example.) Once the person understands himself to be terminated, he had been working here for six years (when he was terminated).
G. Yes, I agree. "for the past six years" (or more often "for the last six years") should be used as "I have been working here for the past six years."