5we haven't visited my grandfather for two months

`->` The last time ...I visited my grandfather two months ago....

6My brother hasn't seen his best friend for nearly five years.

`->` it's ...for nearly five years since my brother saw his best friend.....

7 When did you start learning English?

`->` how long ...have you learned English?...

8. We started living here fifteen years ago.

`->` We have ....lived here for fifteen years.....

...Học tốt...

5. The last time i visited my grandfather was two months ago

6. It's nearly five years since my brother saw his best friend

7. How long have you learned English? 

8. We have lived  here for fifteen years