1. It's been five years since I last did the job as a teacher.
I haven't  done the job as a teacher for  five years
2. I have never seen such an interesting job advertisement.
This is the first time  I have ever seen such an interesting job advertisement.
3. He hasn't visited his farm for a month.
It has been a month since He last visited his farm
4. How long have you worked for this company?
When did you start for this company?
5. This’s the first time I have run my own business.
I have never  run my own business