1. Helen has been washing the dishes for fifteen minutes.
2. My classmates have been writing a dictation since the beginning of the lesson.
3. Sam has been driving a car for five hours now.
4. I have been looking for information on the subject since last Friday.
5. Molly has been painting this picture for three days now.
6. The tourists have been doing the sightseeing since nine o’clock.
7. You have been working as a computer programmer for more than fifteen years.
