Transposer chacune des phrases suivantes à la forme négative contractée du present perfect.
I've been here for hours.
I've studied English for years.
I've loved mangas since I was a child.
I've played the guitar for 3 years.
I've known her all my life.
I've loved this actress for years.
I've been fixing cars for years.
I've been waiting for you for hours.
You've been watching TV all day.
You've been walking the dog.