用所给动词的适当形式填空。
1. I ___________ (be) learning English for five years since I was ten years old.
2. If I don't study hard, I ___________ (not pass) the final exam.
3. I ___________ (study) for my exam when my friend called to invite me to the movies.
4. We ___________ (have) so many exams this year that I am sick of them.
5. It ___________ (be) a nice day yesterday, wasn't it?
6. It's now four o'clock, so we ___________ (be) skating for about two hours.
7. I ___________ (go) to school early today.
8. My friend ___________ (collect) shells as a hobby.
9. We are going to the beach tomorrow, ___________ (be) we?
10. My brother ___________ (be) playing the piano since he was ten.