when have been? is this right expression?

[polease]

Hi I have a question,

I am not a native but am able to speak it to the extent that I could get my ideas acrossed. however the use of have p.p always has bothered me and here is the question

is this "when have been" ok?? is this a grammatically correct expression ?

I did a google search and retrieved few headings with the expression bearing the structure above as follows:-

When have Ice age occurred?

When Have You Been Most Motivated

When have our values so degenerated?

because I thought below was the case regarding the difference in the use of the tenses


- how long? - > have p.p ( flow ) : refers to the duration but cannot be assoicated with the point of time therefore 'when' cannot be used with it

- when - > be ( point ) : cannot serve as an answer to the question starting with "how long"

however the search result seems to contradict what I though was correct

I would like to belive that they are not formal uses , but not neccessarily bad as is the case with the use of "did you ever" while there is a perfect substitute for that term, " have you ever"

am I right ? are they ( the search results) sloppery uses from a few and not a generally recognized rule of proper use of english?

[philo2009]

Yes, the combination is possible, where 'when' refers to the kind of time frame that will/could conceivably recur in the future, rather than a definitively finished past time.

Thus, in asking

When have you been most demotivated?

the speaker is expecting an answer along the lines of 'at times of greatest stress', or perhaps 'whenever I have just had an argument with a colleague'.