Помогите с Present Perfect дам 34 баллаHelen (to wash) the

Помогите с Present Perfect дам 34 балла
Helen (to wash) the dishes for fifteen minutes.
My classmates (to write) a dictation since the beginning of the lesson.
Sam (to drive) a car for five hours now.
I (to look) for information on the subject since last Friday.
Molly (to paint) this picture for three days now.
The tourists (to do) the sightseeing since nine oclock.
You (to work) as a computer programmer for more than fifteen years.
The wind (to blow) since yesterday.
My grandfather (to collect) coins since he was a boy.
Andy and Den (to discuss) the plans for their winter holidays for two hours now.