Write question with yet.
1. Your friend has got a new job. Perhaps she has started it. You ask her :
Have you started your new job yet?
2. Your friend has some new neidhbours. Perhaps he has met them. You ask him:
     ...
3. Your friend must write a letter. Perhaps she has written it now. You ask her:
     ...
4. Tom was trying to sell his car. Perhaps he has sold it now. You ask a friend about Tom:
     ...