Dear Krysstl,
I agree with Edromedina.
For my students, I would keep it simple! I would say that the question: "How long ago did you ... ... ?" is a �WH Question �, because it begins with one of the words, "who/whom/whose; what; which; when; where; why; how",
OR ALTERNATIVELY: it is an Information Question, because the answer supplies information, (as opposed to a "Yes"/"No" Question and Answer).
"How long ago did you ... ... ?"
"Five years � ago, I ... ... "
Quirk et alia, 2010, (in the highly respected �A Comprehensice Grammar of the English Language �), under the heading "Time", page 481-482, discuss "Duration" and write ... ... "Temporal measure is seen as duration. Linking durations to specific positions on the linear time scale, we have the concept of span. .. ... "the FORWARD SPAN, ... until, up to a specified point of time", and "the BACKWARD SPAN, ... since, from a specified point of time".
"... ... Then there are more general expressions of duration, without necessary relation to a particular point of orientation. For example:"
"I am staying (for) three weeks".
"Here, the reference of the adverbial may extend both into the past and into the future from the time point of utterence; equally, it may refer to a three-week period at some unspecified time in the future, just as in the following example it can refer to an unspecified period in the past."
"I stayed (for) three weeks".
"The elicitation of duration as well as forward and backward span is usually achieved by the same question form, �How Long? � (My underlining, Les D.) But for future and past extent, alternative forms are generally available, such as �Till when ... ...? � and �Since when ... ... ? � respectively." ... ...
Although this is a complicated explanation, I hope that it helps you to form a decision.
Les Douglas
