chuyển các câu sau từ thì hiện tại hoàn thành sang thì quá khứ đơn sao cho nghĩa của câu không thay đổi
- we have learned English for 10 years.
- it has been a long time since we last met
- ms.ann hasn't taken part in any voluntary programs for 4 years
- i haven't met my family since lát Christmas
- Hơ long have you lived here?
- the volunteers have provided free frood and fresh water to homeless people since yesterday
- the doctor has quitted his job in the local hospital and moved to the central hospital for 2 days
- the children haven't had a long vacation since last years
- they haven't visited their parents for 3 months
- it has been 2 years since we broke up