2. How long have you been learning English at school?
3. I has been raining all week, so the ground is very wet and dirty.
4. A lot of people have been using cellphone since it was invented.
5. How many quilts have you made today?
6. Have you been doing this boring work all morning?
7. Mother has been cooking this delicious meal for us since 10 a.m.
8. I have been staring at my computer display for hours without a single thought.
9. Have you been thinking about Juliet since your last encounter?
10. Doctors have not found cure for AIDS yet.