Rewrite the sentences:
1. I started learning English three years ago.
->I have ................................
2. I have never met him for three years.
-> I last............................
3. We have studied French for 4 years.
-> We started.....................
4. I haven't seen her for a long time.
-> I didn't.....................
5. They have worked in that factory since 1996.
-> They started.......................
6. How long have you learnt English?
-> How long ago.....................?