`1` Samuel has kept a diary since `1997.`

`2` We have learned English for fìve years.

`3` I have lived in Ho Chi Minh City since I was `8.`

`4` She started teaching the children in this remote village five months ago.

`5` The last time he wrote to me was in April.

`6` She last swam five years ago.

`7` They haven't talked to each other for two months.

`8` She hasn’t seen her elder sister since `1999.`

`9` It’s years since she last wrote to me.

`10` It’s ten years since Robert and Catherine got married.

S + HTHT (phủ định) + for + thời gian.
`to` It’s + thời gian ….+ since …+ last + QKĐ (khẳng định).

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S + HTHT (phủ định) + before.
`to` It’s + the first time + S + HTHT (khẳng định).

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S + HTHT (phủ định) + since / for + …..
`to` S + last + QKĐ (khẳng định) …+ when + mệnh đề.
`to` The last time + S + QKĐ (khẳng định) + was + thời gian.

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S + HTHT (khẳng định) + for + thời gian.
`to` S + began / started + V-ing + thời gian + ago.

1. Samuel has kept a diary since 1997 (hiện tại hoàn thành S+have/has +V3)

2.We have learned English for five years ( hiện tại hoàn thành S+have/has +V3)

3. I have lived  in Ho Chi Minh City since I was 8 ( hiện tại hoàn thành )

4. She started teaching the children in this remote village five months ago. ( Đổi ngược lại như mấy câu trên )

5. The last time he wrote to me was in April. (Cấu trúc : The last time + S + V ( simple past tense / present perfect tense )

6. She last had a swim 5 years ago. ( giống trên )

7. They haven't talked to each other for 2 months. ( giống trên )

8. She hasn't seen her elder sister since 1999.

9. It's ten years since Robert and Catherine were married.