16. How long has it been since you learned to drive?

17. I haven't gone swimming since we were in Spain.

18. It's weeks since you tidied your room.

19. We have looked for a flat for 2 months.

20. I haven't been to a nightclub before.

1. The last time I really enjoyed myself was your birthday party

~ I haven't ..enjoyed myself since your birthday party......
 

 The last time I went swimming was when we were in Spain.

-> I haven’t gone swimming since we were in Spain

 

You haven't tidied this room for weeks.

-> It’s weeks since you last tidied this room

3. We started looking for a flat 2 months ago and we are still looking.

-> We have been looking for a flat for 2 months now