1. I have learnt English since 2000.
2. My sister has taught English for 20 years.
3. It has been raining for an hour.
4. They started building this hotel one year ago.
5. He started having his breakfast when it was 7 o'clock.
6. Mr. Ba started talking to our teacher one hour ago.
7. We have worked here for 2 years.
8. He hasn't gone abroad before.
9. She has driven for 1 month.
10. We have been eating since it started to rain.