2. Our TV hasn`t worked very well recently
3. ... I`ve lost my keys (т.к. тут не страдательный залог)
4. Do you think I should sell my computer?
5. My friends hasn't emailed me.
6. We've tried. (без been)
7. ... You should take... (так как совет)
8. Have you been crying ( Presen Perfect Continious так как видимый результат)
9. You should not tell anyone