I. Решение:
- We have not finished decorating the classroom yet. We have been decorating it for two hours.
- Kate rides her bike to school every day. She has been using this bike for five years.
- Has your friend done his homework yet?
- My cousin went to London twice. Last year she did it right now.
Ответ: have not finished, have been decorating; rides, has been using; Has your friend done; went, did.