SHORT ANSWER:
Yes, the continuative present perfect may be used to signify a state which continues right up to the present regardless of whether it continues in the present. It is not, however, used to signify a state which does not continue right up to the present.
LONG ANSWER:
The 'continuative' present perfect establishes the past event or events it names as a state which endures right up to the present.
Situations grammatically depicted as states are presumed to continue indefinitely, until something happens to end them.
Consequently, the present perfect permits you to infer that the state it describes continues in the present. In fact, this is the default assumption with an unqualified present perfect. If you had only the statement “I've been driving a hearse for the last 25 years” you would legitimately infer that he is still driving a hearse.
But the present perfect does not entail—logically require—the continuation. Linguists call this an implicature, as opposed to an implication: it is in inference which may be cancelled by a contrary fact. That's what you have here, with the statement “Today is my first day driving a cab.”
Note, by the way, that there is in this particular use of the perfect, no difference between the use with the progressive, “I have been driving”, and without it, “I have driven”. The phrase “for the last 25 years” imposes the same continuative reading on both.
Note, too, that because the hearse-driving does not continue into the present the speaker might with propriety have employed the ‘simple past’: “I drove a hearse for 25 years.” I suspect he uses the perfect (and the progressive) because what he wants to convey is that there is a continuity in his activity: “I’m still driving, what’s changed is that now I’m driving a cab.”
Note, finally, that the notion of ‘present’ is defined pragmatically. Obviously when someone says he has driven a hearse for 25 years he does not mean that he drove continuously throughout that period. By the same token, the ‘present’ which that driving continued ‘right up to’ is not the moment in time when the statement is uttered but “today”
The case of John’s tardiness is a little different. In the circumstances you describe, neither the continuative present perfect nor the phrase “for the last 30 minutes” is proper. You are dealing with a much different timeframe and scale than the cabdriver. Your answer (“alas”) makes it clear that you are pragmatically defining three distinct epochs: 1) you wait for 30 minutes 2) you depart, and a couple of minutes elapse—long enough, at any rate, that you are no longer in the vicinity of the appointed meetingplace 3) then John calls. Consequently, the state of waiting (1) did not continue “right up to” the present (3).
Here are some ways you might express the facts:
I waited for you for thirty minutes, but, alas, when you didn’t show up I left.
I waited for you for thirty minutes, but, alas, I’ve left now.
I waited for you for thirty minutes, but, alas, I had to leave.
You should not employ the progressive I was waiting here; that is employed to speak about something which happened while you were waiting.
Now could you explain me why in the fifth sentence (the one that begins with Apparently) drive and splash are past perfect ...
Without a great deal more context why is a matter of conjecture; but we can certainly address how.
You understand, I take it, why the past perfect is employed with waiting: this establishes that the events which the narrator is about to recount occurred prior to RT (Reference Time, the time the narrator is talking about, when the boyfriend arrived) and gave rise to the boyfriend’s state at RT.
- Note that even this perfect is not obligatory; in conversation, at least, the narrator might cast WAIT in the past progressive without taxing her hearer's comprehension; but the perfect is a conventional and efficient way of laying out the time relationships.
Once the 'background' anteriority of waiting has been established, the narrator has a choice of constructions for continuing the boyfriend’s narrative. She may, as she does in your example, persevere with perfects, maintaining a consistent relationship with the established RT. However, she may also take the time of waiting to be a new, temporary, RT—a sort of sub-RT—and move the narrative forward with simple or progressive pasts until she arrives once more at the original RT.
There is no “rule” to say that one choice is the better than the other. The difference is one of focus:
- with pasts, the focus is on the prior events as narrative, the boyfriend’s chain of unhappy experiences;
- with perfects, the focus is on the prior events as explanation, either why the boyfriend is soaked, or the narrator’s hearing the explanation as it is offered.
Best Answer
Your interpretation is correct, but is only one possibility. This will either mean that
1) Between last Thursday and today, you have been on 4 dates, or
2) Between the start of the current week and today you have been on four dates. (Since Sunday or Monday, depending on where you are)
Your interpretation of this is wrong. If you said "Last Thursday, I went on four dates," it would mean you went on all four dates on that single day. But saying last week refers to the full time span of the last week.
There are a couple likely interpretations.
1) During the previous calendar week (Sunday to Saturday or Monday to Sunday) you went on four dates, on any combination of days.
2) From the previous Thursday to today, you've been on four dates.
In short, the two mean the same thing if you are counting back from the current Thursday, but refer to different weeks if you are using calender weeks starting on a Sunday or Monday. And without further context, a listener won't know exactly what you mean. In many cases, this doesn't matter: they still know you went on a lot of dates recently.
The best rule of thumb is that if the differences matter, don't use these constructions because they are open to interpretation. Specify that you mean "Between last Thursday and today, I went on four dates."