$1.$ It's five years since I last saw Rosa.

$2.$ It's a year since we last went to the cinema.

$3.$ It's twenty years since John last was back to his village.

$4.$ It's an age since I last saw you.

*Cấu trúc:

$-$ It is + time + since + S + last + V (-ed/ bất quy tắc) $⇔$ S + haven't/ hasn't + V (Pii) + since + time.

$-$ "Đã bao lâu kể từ lần cuối làm gì đó $⇔$ Đã không làm gì được một thời gian".

$============"$

$1.$ Before the workers went out for dinner, they had finished their work.

$2.$ Before Steven bought a new car, he had saved enough money.

*Cấu trúc:

- Kết hợp thì quá khứ đơn và thì quá khứ hoàn thành để diễn tả một hành động xảy ra trước một hành động khác trong quá khứ.

  + Hành động xảy ra trước dùng thì quá khứ hoàn thành: S + had + V (Pii).

  + Hành động xảy ra sau dùng thì quá khứ đơn: S + V (-ed/ bất quy tắc) 

1IT'S 5 YEARS SINCE I SAW ROSA

2IT'S OVER A YEAR SINCE WE WENT TO THE CINEMA

3IT'S NEARLY TWENTY YEARS SINCE JOHN WAS BACK TO HIS VILLAGE

4IT'S AGES SINCE I SAW YOU

1 BEFORE THE WORKERS WENT OUT FOR DINNER, THEY FINISHED THE WORK

2 BEFORE STEVEN BOUGHT A NEW MOTOBIKE, HE SAVED ENOUGH MONEY