The Present Perfect after “since”.

[Humble]

Dear teacher, or somebody who knows,
Here is a sentence written by an American:
It’s only been a few years since I’ve been in high school; I am currently in college.
I do not understand why the Pr.Perfect is used after since.
Besides, is in school, in college an AmE feature? AFAIK , at school, at college.
Be so kind to explain, will you?

[Tdol]

I wouldn't use the present perfect there because it refers to something completed in the past. However, you can use the present perfect after since:
Since I've been working with him = unfinished

At is the normal prepositions, but you will hear people using in. I personally wouldn't use it there- I study at college (generally) I am in college (actually present at time of speaking)

[Humble]

Thank you, tdol. Your style is particularly concise, you must be very busy as editor.
I still have some questions.
1. I've seen the Pr.Perfect after since quite a few times and it appears to be not a rare occurrence among native speakers. Could you recommend a source to read about it in-depth?
2. As to your example, I didn't understand it, because the sentence is not complete. Could I complete it this way:
I've gained a lot of experience since I've been working with him.
BTW since is ambiguous here, isn't it? One can understand it as because.
Sorry to be pestering you .

[Tdol]

I've gained a lot of experience since I've been working with him.

This could be ambiguous, but it is a perfectly fine sentence when describing the time period. I don't know of any sources as people tend to say that the past should be used and forget that the present perfect can be used.

[Ouisch]

It's only been a few years since I've been in high school; I'm currently in college.

Tdol is correct; the original speaker shouldn't have used the present perfect. The sentence as written doesn't make sense, since he can't be in high school and college at the same time. He should've said: "It's only been a few years since I was in high school; I'm currently in college."

We (in the US)do say "in college" or "in high school," and not "at," however.

[Humble]

Thank you, Ouisch.
Then, how could such a mistake be explained - it's not a typo just to wave it off.
I'll give another example (Sinead O'Connor):
Since you've been gone I can do whatever I want
I perceive the lover's departure as a starting point of some new situation, and those points are some events in the past ,so they should take the Past Simple, shouldn't they?
Ambiguously, we can understand since as because.
I don't know, perhaps lyrics often sacrifice grammar for the sake of rhythm or whatever...

[Tdol]

With the first, it could just be a case of native speaker error. You will see 'I would of known' and other things used by native speakers. David Backham recently invented a conditional form (If I had have known). With the second, I think it can be explained in a different way- 'gone' is an adjective (like 'away/missing/absent') and it describes the state of absence not the act of leaving. Then again, lyrics do all sorts of things grammar says they shouldn't.

[Humble]

Tnx vy much indeed, tdol.