There is a very good chance that Mary left the apple. We doubt that Lily is yellow. We believe that Sandra took the milk. It is probable that if 'Mary left the apple' or 'Sandra took the milk' or both then Winona is a wolf. Chances are slight that if 'Mary left the apple and Lily is yellow' then Julius is a frog. There is a very good chance that if 'Sandra took the milk and Lily is yellow' then Brian is a rhino.
We doubt that 'Sandra took the milk' or 'Julius is a frog' or both.
We believe that 'Sandra took the milk' or 'Julius is a frog' or both.
We doubt that 'Sandra took the milk' or 'Julius is a frog' 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
  0.8::factA.
  0.2::factB.
  0.75::factC.
  %hop1
  0.7::factX:-or(factA,factC).
  0.1::factY:-and(factA,factB).
  0.8::factZ:-and(factC,factB).

  %hop2
  conclusion:-or(factC,factY).

  query(conclusion).
  
'Sandra took the milk' or 'Julius is a frog' or both.