I have
For
For a period of time
I haven’t been skiing for four years
I have been working down the mines for 35 years.
Since
From a point of time until now.
I haven’t skied since I was seven years old.
I have been working down the mines since I was a young child.
For and since questions
1) How long is it since you went to school?
2) How long have you worked at De Heus for?
3) When did you pass your driving test?
4) When did you first realise you wanted to work in a laboratory testing animals food?
5) How long is it since Barcelona FC won the league?
6) How long have the lorry drivers been on strike for?
present perfect continuous
Example: I have been working as in English teacher in the north of Spain since