$ echo Washington werewolves are wasteful | perl -pe 's/w(as|ere)/be/gi;'
behington bewolves are beteful
$ echo No work was carried out on Thursday as that as a day of rest | perl -pe 's/\s.*work.*/ work /gi;'
No work 
$ echo Did you swallow all that bacon | perl -pe 's/\s.*allow.*/ allow /gi;'
Did allow 
$