Chuyển các câu sau từ thì hiện tại hoàn thành sang thì quá khứ đơn sao cho nghĩa không đổi.
1. We have learned English for 10 years
2. it has been a long time since we last met
3. ms.ann hasn't taken part in any voluntary programs for 4 years
4. i haven't met my family since last chrismas
5. how long have you lived here?
6. the volunteers have provide free food and fresh water to homeless people since yesterday
7. the doctor has quitted his job in the local hospital and movedd to the central hospital for 2 days
8. the children haven't hqad a long vacation since last year
9. they haven't visited their parents for 3 months
10. it has been 2 years since we broke up.