2. They have been watching a comedy for over an hour.
3. Annie has been doing her homework since 10 o'clock this morning.
4.How long has he been working as a doctor?
5. The children have been studying since breakfast.
6. We have been thinking of buying a house since last year.
7. Have you been feeling ill for a long time?
8. Chris has been trying to fix the motorbike since Tuesday.
