how to prevent expired domain from losing backlinks?

There are 2 kinds of expired domains: those who lose a significant number of their backlinks over time, and those who don't lose a significant number of their backlinks over time.

1) How can you tell if an expired domain that you are considering will lose its backlinks?
2) How can you make it keep its backlinks? I guess you have to put the site back up and pretend you are the original site so webmasters don't remove your links but that's kind of risky because the original owner might find out.

I dont know, any ideas?

You're asking a question, no one can answer. How are we supposed to know when a site owner will remove a link to a site.
If they see the site is expired and no longer up, they'll remove their link.