1. The present perfect continuous is formed using has/have + been + present participle.
2. We use since + a specific time (e.g April 2)
We use for + a length of time (e.g 2 days)
3. "For how long have you been working?"
study:
(a fost deja folosit)
work:
I've been working there since a year ago.
play:
We've been playing computer games for a day.
live:
She's been living in the virtual world since 2004.