( )1. ---How long have you been in this city?
---___________twenty years.
A. For B. Since C. Before
( )2. He _________our school for two years.
A. left B. had left C. has been away from
( )3. When I was walking in the street, I saw a plane ________over my head.
A. flying B. to fly C. flew
( )4. --- I have finished my homework.
--- When ______you _______ it?
A. will; finish B. have; finished C. did; finish
