Помогите сделать британский!Choose the correct verb form.1. How long has Omar

Помогите сделать британский!
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.