EX15. Chuyển các câu sau từ thì hiện tại hoàn thành sang thì quá khứ đơn sao cho nghĩa của câu không thay đổi.
4. I haven’t mer my family since last Christmas.
=> ____________________________________________________________________.
5. How long have you lived here?
=> ____________________________________________________________________.
6. The volunteers have provided free food and fresh water to homeless people since yesterday.
=> ____________________________________________________________________.
7. The doctor has quitted his job in the local hospital and moved to the central hospital for 2 days.
=> ____________________________________________________________________.
8. The children haven’t had 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.
=> ____________________________________________________________________.
