Student or Learner
- He had unforgetable experiences in his military service.
Is it OK to use 'in' in the sentence above or should I put 'during or over' instead?
- He had unforgetable experiences during his military service.
- He had unforgetable experiences over his military service.
'...during' is by far the best.
'...in' is just about possible.
'...over' is not acceptable.