4.it's seven months since we started doing this research

2 song hye kyo last wrote to me one year ago

the last time song hye kyo wrote to me was one year

it's one year since song hye kyo last wrote to me

it's has been one year since song hye kyo last wrote to me

3 the last time he left his town was twelve years

it's twelve years since he left his town

he last left his town twelve years ago

4 I last saw my father one month ago

the last time I saw my father was one month

it is one month since I last saw my father

5 we haven't gone to the cinema for fifteen years

the last time we went to the cinema was fifteen years

6 we have not seen daniel since 1995

we last saw daniel was 1995

7 we haven't washed our car since monday