The classmates ...... (not / study) together since 2002 when they had a fight over a girl.

The magician ...... (not / perform) on stage for well over a year now.

The cleaning lady ...... (not / work) here for three weeks.

The children ...... (sleep) in their room since eight o'clock.

I ...... (check) your work since October last year.

Jason ...... (supervise) my department for over six months now.

Since when ...... (your neighbours / celebrate) so many late night parties?

Since when ...... (she / write) poems?

Since when ...... (you / ride) a horse in the city?

How long ...... (they / sell) drugs to young children?

How long ...... (your brother / work) on the farm?

How long ...... (you / study) French now?