It is probably not the case that Mary grabbed the milk. It is probably the case that Sandra dropped the milk. It is impossible that Lily is yellow. It is almost certain that if 'Sandra dropped the milk and Mary grabbed the milk' then Greg is a frog. We believe that if 'Lily is yellow' or 'Mary grabbed the milk' or both then Brian is a swan. It is unlikely that if 'Lily is yellow and Mary grabbed the milk' then Emily is a cat.
It is likely that 'Sandra dropped the milk' or 'Emily is a cat' or both.
It is likely that 'Sandra dropped the milk' or 'Emily is a cat' or both.
It is probably not the case that 'Sandra dropped the milk' or 'Emily is a cat' or both.

  and(A,B) :- A,B.
  or(A,B) :- A;B.
  nand(A,B) :- not(and(A,B)).
  nor(A,B) :- not(or(A,B)).
  xor(A,B) :- or(A,B), nand(A,B).

  %hop0
  0.25::factA.
  0.7::factB.
  0.0::factC.
  %hop1
  0.95::factX:-and(factB,factA).
  0.75::factY:-or(factC,factA).
  0.2::factZ:-and(factC,factA).

  %hop2
  conclusion:-or(factB,factZ).

  query(conclusion).
  
'Sandra dropped the milk' or 'Emily is a cat' or both.