Помогите сделать английский!
Choose the correct verb form.
1. How long has Omar been studying\does he study\ at school #15?
2. My friend has been looking\looked\ for a bike for 3 weeks.
3. I whore\have been writing\ this exercise since 4 o'clock p.m.
4. I am tired because I wrote\have been writing\ this exercise since 4 o'clock p.m.
5. My friend is working\has been working\ as an air hostess since last month.
6. I have bought\bought\ a dictionary a few months ago.