1. The last time I saw him was in 1995.

- I haven't...seen him since 1995..........

 2.  When did you start learning French?

-How long have you learnt F ?
 

1. The last time I saw him was in 1995

--> I haven't seen him since 1995.
2. When did you start learning French ?
=>How long did you start leaning French? 
3.He learned to drive when he was eighteen.
->He has ……learned to drive since he was eighteen
4. I last wrote to my uncle in July

->I haven't ..written to mu uncle since July.
5.