It is probably the case that Mary dropped the milk. It is certain that Greg is a frog. We believe that Antoine is hungry. It is probably the case that if either 'Greg is a frog' or 'Mary dropped the milk' but not both then Sandra left the apple. It is probable that if either 'Mary dropped the milk' or 'Antoine is hungry' but not both then Lily is a lion. It is highly likely that if 'Antoine is hungry' or 'Greg is a frog' or both then Bernhard is white.
It is likely that 'Sandra left the apple and Bernhard is white'.
We doubt that 'Sandra left the apple and Bernhard is white'.
It is likely that 'Sandra left the apple and Bernhard is white'.

  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
  0.7::factA.
  1.0::factB.
  0.75::factC.
  %hop1
  0.7::factX:-xor(factB,factA).
  0.7::factY:-xor(factA,factC).
  0.9::factZ:-or(factC,factB).

  %hop2
  conclusion:-and(factX,factZ).

  query(conclusion).
  
'Sandra left the apple and Bernhard is white'.