1.On the way to work, Tom met his former teacher (walking)
>Tom met his former teacher.......to work
2. I started working in this school 20 yesrs ago. (Been)
>I......in this school for 20 years.
3.We haven't gone to the cinema for over a year (last)
>It's over a......to the cinema
*đề yêu cầu: you must use between TWO and FIVE words, including the word given
1.On the way to work, Tom met his former teacher (walking)
>Tom met his former teacher....when he was walking...to work
2. I started working in this school 20 yesrs ago. (Been)
>I...have been working...in this school for 20 years.
3.We haven't gone to the cinema for over a year (last)
>It's over a...year since we last went...to the cinema
Cho mình hỏi câu 2, tại sao ko dùng have worked mà phải dùng have been working v ạ, have been working ở trong thì nào v ạ